A/B testing is a method used in marketing and product development to compare two versions of something, like a webpage or an app, to see which one performs better. Essentially, you show version A to one group of users and version B to another, then measure which version gets a better response. It helps businesses make data-driven decisions by testing variations and optimizing for better results.
A-D
Analog-Digital.
A-filter
See A-weighting.
A-Format
A microphone arrangement with four coincident cardioid capsules. Using a dedicated matrix, this signal can be converted to B-format. See Sound Field Microphone.
In film or video projects, A-roll is all the main footage, basically shot by an A-camera. The B-roll refers to any footage shot by a B-camera or any other supplemental footage to the A-roll. In larger productions with more photographers or filming crews, the crew shooting the B-roll is usually called the "Second unit".
A-weighted Sound Pressure Level
Sound pressure level measured with an A-weighting function involved. (See A-weighting).
A-Weighting
A-weighting is a filtering or a filter function inserted in the signal chain. It applies in particular to the measurement of acoustic noise at the workplace and the environment. However, it also applies to the measurement of noise in microphones. To some degree, the A-weighting filter mimics the frequency response of the human ear at lower levels (the 30 phon equal loudness curve) (see Equal Loudness Contour).
B- and C-weighting curves belong to this family of curves; however, these were developed to be used at higher levels.
A-weighting is specified in IEC 60 651, but references are also made in other standards like ANSI S1.4-1981.
Measurements performed with A-filters are often described with an "A" in parentheses, for example, xx dB(A) or with an "A" as an index, LA = xx dB.
In production for theatre: A1 is the person that makes the audio mix. A2 is usually the backstage assistant who performs cable checks, mic placement, etc.
AAC
Advanced Audio Coding. Special variant of the MPEG standard.
AB
1. A microphone setup for time difference stereo.
2. A method for powering microphones (±12 volt on the signal leads), also called Tonader.
3. A method for comparison of two versions.
(symbol: α) The practical unit between 0 (no absorption) and 1 (full absorption) expressing the absorbing properties of a material. This is basically specified per octave or 1/3 octave. Absorption may exceed 100% (or a >1) when the surface area seems larger than the area it covers (applies typically only at high frequencies).
Acoustic equalizers or acoustic pressure equalizers (APEs) are sphere-shaped accessories designed for use with omnidirectional microphones. They result in higher directivity in the upper part of the frequency range and an upper midrange frequency boost.
A principle of controlling the directivity of a microphone by changing the admittance of sound to the back of a microphone diaphragm, for instance, switching from omnidirectional (only frontal sound, no sound entering the rear) to a cardioid (some sound reaching the backside of the diaphragm). Schoeps has been especially clever using this principle for single-diaphragm microphones.
Active Drive
Active drive is a technology implemented in microphone preamplifiers.
Electrostatic actuators are used to simulate the pressure response of condenser microphones. This is done by exerting an oscillating electrostatic force in front of the microphone's diaphragm and measuring the subsequent response of the microphone.
ADC
Analog to Digital Converter (see this).
ADPCM
Adaptive Differential Pulse Code Modulation (see this).
ADR
Automatic Dialog Replacement (see this).
AES
Audio Engineering Society (see this).
AES/EBU
AES/EBU The AES (Audio Engineering Society) and EBU (European Broadcast Union) created jointly a standard for the transfer of two channels of digital sound. The signal is bi-phase modulated, self-clocking and runs on a balanced cable (max. 50 m or 150 ft) or via optical fiber. The standard currently is called AES3.
AES67
AES67 is a technical standard for audio over IP (AoIP) and audio over Ethernet (AoE) interoperability. The standard was developed by the Audio Engineering Society and first published in September 2013. It is designed to allow interoperability between various IP-based layer 3 audio networking systems such as RAVENNA, Livewire, Q-LAN and Dante. It also provides interoperability with layer 2 technologies, like Audio Video Bridging (AVB).
AF
Audio Frequency (see this).
AFM
Audio FM (see this).
Aging
See Surround Sound.
AIFF
Audio Interchange File Format (see this).
Ambience
Spatial effect, notably mixing of remotely placed microphones in order to include the atmosphere of the room on the recording.
For an alternating signal: the size of the variation.
Amplitude Modulation (AM)
Transfer of information by the variation of the amplitude of a carrier wave.
Analog
Quantities in two separate physical systems that have consistently similar relationships to each other are called analogous. One is then called the analog of the other.
Example: The sound pressure in front of a microphone and the electrical output of that microphone.
Analog to Digital Converter (ADC)
A circuit that converts an analog signal to a digital signal.
Anchor Element
The perceptual loudness reference point or element around which other elements are balanced in producing the final mix of the content. Alternatively, that which a reasonable viewer would focus on when setting the volume control.
A room in which all surfaces are absorbing the sound, thus providing reflection-free conditions. The anechoic room substitutes the outdoor free field. The reverberation time is as close as possible to zero seconds. The room is typically used for acoustical measurements of, for instance, microphone properties and psychoacoustic experiments.
American National Standards Institute is a federation of American organizations concerned with the development of standards.
Antenna Diversity
See Diversity.
Antenna Length
In wireless audio: The physical length of an antenna is strongly related to the wavelength of the radio wave. Most applied are half-wave or quarter-wave antennas.
Anti-aliasing
In digital audio: Low-pass filter for the removal of frequencies that otherwise would create "alias" frequencies that were not present in the signal originally.
AoIP
Audio over Internet Protocol - term for Audio in IP-based networks.
APT-X
Proprietary audio codec, provides bitcompression scheme often applied to Digital Cinema, Blutooth and other wireless applications, like wireless microphones. The first version of this codec was developed by Queen’s University Belfast.
AR
Augmented Reality, see this.
Array Microphones
Multiple microphones (from two to hundreds) arranged to obtain directionality, either by direct summing of all microphone's signals or by adding signal processing to the summation process. Examples of arrays:
Endfire microphone: Microphone elements arranged in a straight line, all units time-aligned to the element furthest away from the sound source.
Sphere microphone: Microphone elements distributed on the surface of a rigid sphere. (Typical sizes: 10-25 cm diameter). The use of signal processing then obtains beamforming. The signal can be extracted into several audio channels providing multichannel options.
Unwanted effects that arise due to technical limitations.
ASCII
American Standard Code for Information Interchange. Character set encoding used in data transfer.
ASIO
Audio Stream Input/Output (see this).
ASK
Amplitude Shift Keying. In digital transmission, a method for modulating a digital signal onto an analog carrier.
Asynchronous Sample Rate Converter
When two (digital) devices cannot be synchronized (for example, a CD player with a mixer) even a small deviation between the clock frequencies of the two devices will cause occasional glitches due to the accumulation of shortages or excesses. The asynchronous sample rate converter can perform interpolation, and hence create the missing intermediate values so that glitches are avoided.
ATR
Audio Tape Recorder.
ATRAC
Adaptive Transform Acoustic Coding. Bit reduction system from Sony for use on MiniDisc. In stereo, 300 kbps is used. The system is also used for films. See SDDS.
ATSC
Advanced Television Systems Committee.
Attack
A dynamics descriptor. Transient response. Specifies whether the drumbeats and percussion, etc. are accurate and precise, i.e., if you can hear the actual strokes from the drumstick, the plucking of the strings, and such. It is also expressed as the ability to reproduce each audio source transient cleanly and separated from the rest of the sound image. Imprecise Attack is understood as having an unclear or muted impact.
Scale applied in listening tests: Imprecise - Precise.
[Reference: Report ITU-R BS.2399-0]
Attenuate
To reduce the level of an electrical or acoustical signal.
Attenuator
A device used to control the level of an electrical signal.
Audibility Threshold
The sound pressure level, for a specified frequency, at which people with normal hearing begin to respond.
That part of sound technology that concerns itself with the recording and reproduction of sound.
Audio Bridge
Dialogue or sound effects in one scene that continues over into a new shot. In this case, the soundtrack connects the two scenes.
Audio Engineering Society
A society for audio professionals.
Audio FM (AFM)
Designation for a video recorder's frequency-modulated sound track.
Audio Frequency
Audible frequencies, basically in the range of 20 Hz to 20.000 Hz. In connection with wireless systems.
Abbreviated AF.
Audio Interchange File Format (AIFF)
An uncompressed audio format developed by Apple.
Abbreviated AIFF.
Audio Stream Input/Output (ASIO)
ASIO is a PC sound card driver protocol for digital audio. It provides a low-latency and high-fidelity interface between a software application and a computer's sound card. Steinberg initially designed this standard.
Auditory Fatigue
A reduction in the sensitivity of the human auditory system caused by prolonged exposure to sound.
An additional layer on top of reality; the physical world mixed with virtual elements. The virtual elements can be presented to the user, for instance, by smartphones (with GPS), so different effects are site specific.
Autolocate
Facility on a tape unit's transport system.
Automatic Dialog Replacement (ADR)
Automatic replacement of location dialog with studio dialog. ADR can be carried out either for technical or creative reasons; it is sometimes used to change dialog during the editorial process.
Automatic Gain Control (AGC)
Method by which the amplification in a circuit is controlled by the input voltage or another parameter.
AUX
Auxiliary jack, an extra input or output.
AVB
Audio Video Bridging. An interface standard for the exchange of both sound and images, especially over shorter distances (usually max. 15 meters in cable).
AVI
A video-file in the Audio Video Interleave-format containing both video and audio. First developed by Microsoft in 1992.
Azimuth
Angle of a magnetic head gap in relation to the direction of travel of a magnetic tape.
Bb
See all in B
See all in B
Microphone Dictionary
Bb
B-format (microphones)
A recording format virtually based on three orthogonally-oriented figure 8 microphones (X, Y, Z) and one omnidirectional microphone (W). By combining these signals a variety of directional characteristics can be obtained. Most B-format microphones are designed with cardioid microphones.
See Sound Field Microphone.
An expression related to the directivity pattern of antennas and microphones. The back lobe shows the sensitivity versus angle to signals coming from the back.
First-order microphones (except for omnidirectionals) have a main lobe (on-axis direction) and a back lobe. Higher-order microphones (and antennas) also have side lobes.
Background Sounds
Sounds at a level that is low, relative to the foreground sounds, which are incidental, or which are not required for understanding or appreciation of the program. This would include content such as background music in film, wind noise, and more. Dialogue may be a background sound, for example when it consists of background voices in a public space, a restaurant, theatre, etc.
[Source: EBU Wiki - Technical - Louddrafting]
Baffle
1. A movable barrier used in the recording studio to achieve separation of signals from different sources (sometimes called “gobo”).
2. The surface or board on which a loudspeaker or a microphone is mounted.
3. A round disc with a diameter similar to the human head to be placed beween two microphones providing a sort of head related channel separation (The Jäcklin disc).
A spatial descriptor in audio assessment. Is the soundstage skewed to one side (left or right) or is it centered in the middle?
Scale applied in listening tests: Left - Center - Right.
[Reference: Report ITU-R BS.2399-0]
Balanced and Unbalanced Lines
Balanced line is a transmission line consisting of two conductors of the same type and equal impedance to ground and other circuits. The balanced impedances to ground minimizes interference pickup.
When using balanced lines, the shield is not a part of the circuit. Induced electromagnetic noise is rejected due to the common mode, the fact that the impedance is exactly the same between each leader and ground. This is called common mode rejection.
The spacing between the frequencies at which a response attenuates by 3 dB.
Bass Depth
A timbre descriptor (bass range) in audio assessment.
Denotes how far the bass extends downwards. If it goes down in the low end of the spectrum, there is great depth. Should not be confused with Bass strength, which indicates the strength of the bass or Boomy which relates to resonances in the lower bass region.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0]
Bass Management
A circuit that utilizes the subwoofer in a 5.1 (or higher) system to provide a bass extension for the five main speakers. The Bass Manager steers all frequencies below a selected frequency, such as 80 Hz, into the subwoofer along with the LFE (See LFE) source signal.
Bass Precision
A dynamics descriptor, a parameter for listening tests.
Are instrument impacts from the bass drum and bass precise, crisp and without distortion, are the impacts tight and well defined? Bass precision may be defined as Attack in the bass region. Imprecise means that the attack speeds in time and the peak of the impact is softened.
Scale applied in listening tests: Imprecise – Precise
[Reference: Report ITU-R BS.2399-0]
Bass Redirection
Another term for bass management, see this.
Bass Strength
A timbre descriptor (bass range) in audio assessment.
The relative level of bass, i.e., the low frequencies, for example male voices, bass guitar, bass drum, timpani and tuba. Should not be confused with bass depth that indicates the low frequency bass extension.
Scale applied in listening tests: Soft – Loud
[Reference: Report ITU-R BS.2399-0]
Batch
The number of sound or video media produced in the same fabrication process.
BCD
Binary Coded Decimal. Decimal digits converted to the base two system.
Beamforming
Generating specific directional characteristics based on the combination of signals for microphones in a microphone array (see this).
A compact wireless transmitter for lavalier microphones. Often attached to the belt but can also be attached other places.
Bias
1: In magnetic recording: A high-frequency, alternating current (typically 100 kHz) that is added to the recording head in a tape recorder together with the sound signal. It improves the quality of the recording with respect to both frequency response and distortion.
2: In assessment of audio: Making decisions based on irrelevant underlying preferences or predjudices.
Bidirectional Microphone
A microphone with a polar pattern like the figure-of-eight. One lobe is in-phase with the acoustic signal; the other lobe is out-of-phase. Also called a Gradient Microphone (see this).
Piezoelectric microphones are built on the principle of voltage generated by the flexing of piezo crystals. Typically, the piezo element consists of two quadratic crystal layers closely cemented in three corners. The fourth corner is affected by the moving diaphragm. This bimorph element provides a push-pull voltage output when sound moves the diaphragm.
Binary
Number system that only contains two digits.
Binaural Recording
Stereo recording using either an artificial head with built-in microphones or a real person with small microphones in – or close to – the ear canals. For correct monitoring, the recording must be reproduced using headphones to eliminate crosstalk.
A form of modulation that, among other things, is used by the AES/ EBU interface and time code. In the bit stream, each bit shift is marked with a level shift (from high to low or vice versa). If the bit value is high, this is marked with a level shift in the middle of the bit concerned. Some of the advantages include the DC component in the signal is minimized and the signal is self-clocking.
Bit
Smallest unit in digital technology, with a value of either 0 or 1.
Bit Companding
A technique for digital audio via which greater contrast can be obtained for a given number of bits.
Bit Reduction
As linear quantization can result in a larger number of bits per second than there is room for in a transmission channel or on a storage medium, the number of bits is reduced, preferably in a manner so that it cannot be heard in the audio signal.
Bit Stream Converter
See Delta-Sigma Converter.
Blast Shield
Protective tool to place in front of a microphone to avoid excessive air blows to reach the microphone diaphragm. Also called a Pop Filter.
Blimp
Due to its shape, a windshield for long microphones like shotguns is often called blimp or zeppelin. The term blimp (or barney) is also used for sound dampening cover/carpet to put over a noisy film camera.
BLM
See Boundary Layer Microphone.
Blumlein
Microphone configuration named after the inventor Alan Dower Blumlein (1903-1942). In this configuration, two coincident, bi-directional microphones are placed in an orthogonal arrangement of microphone axis.
BNC
The BNC connector is a bayonet-locking type for two-conductor coaxial cable, introduced in the late 1940'es. The name BNC is an abbreviation that has, over time, gotten several explanations; here are some of the more plausible: Baby N Connector (with reference to the bigger-sized N-connector used primarily for RF-connections), Bayonet N Connector, and Berkeley Nucleonics Corporation (the name of a primary equipment vendor).
Body Pack
See Belt Pack.
Boom
A long handheld pole for microphones, often used in film production. The operator is often called boom operator or boomer.
Boomy
A timbre descriptor (bass range) in audio assessment.
Resonances in the low bass, as if the sound was played in a large barrel, which gives a prominent bass resound (reverberating) when bass and bass drums are heard. The representation tends to become muddy and imprecise.
Scale applied in listening tests: None – Weak – Loud
[Reference: Report ITU-R BS.2399-0]
Bootleg
An illegally copied, unauthorized, and/or distributed version of a copyrighted film/video/music track. These are often of lower quality. Also termed pirated.
Bottleneck
1: A short metal tube (originally a glass bottleneck) used to touch the strings when playing the slide guitar or for use with ordinary guitar in folk music. Also called a slide.
2: A region in a singer's pitch range where a register change is mandatory. [Source: National Center for Voice and Speech]
Boundary Layer Microphones
Microphones placed directly on the surface of a large boundary (like a table- or wall surface). They are also called Pressure Zone Microphones or PZM microphones (PZM is a trademark of Crown). Due to the microphones position flush or close to the boundary layer, direct sound is gained by 6 dB and diffuse sound is gained by 3 dB.
A timbre descriptor (bass range) in audio assessment.
Boxy denotes a hollow sound, as if the sound was played inside a small box. Represents resonances in the upper bass frequency range.
Scale applied in listening tests: None – Weak – Loud
[Reference: Report ITU-R BS.2399-0]
Breathy Voice
The result of a widened glottis with excessive airflow that produces air turbulence. [Source: National Center for Voice and Speech].
Brilliance
A timbre descriptor (treble range) in audio equipment assessment: Treble or high frequency extension.
Scale applied in listening tests: A little: As if you hear music through a door, muffled, blurred or dull. A lot: Crystal-clear reproduction extended treble range with airy and open treble. Lightness, purity and clarity with space for instruments. Clarity in the upper frequencies without being sharp or shrill and without distortion.
[Reference: Report ITU-R BS.2399-0]
BS.1770
Formally ITU-R BS.1770. This specifies an algorithm that provides a numerical value indicative of the perceived loudness of the content that is measured. Loudness meters and measurement tools that have implemented the BS.1770 algorithm will report loudness in units of "LKFS".
A signal-related descriptor in audio assessment: Sound or noise with fast (<1 sec.) variations in frequency and/or loudness.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
Buffer
Circuit for the maintenance or improvement of a function.
Bus
A common set of conductors where many signals are gathered, for example in a mixer console.
Buzz Track
In film: A soundtrack of natural, atmospheric, on-location background noise that is added to the recorded track of actors' dialogue and other sound effects recordings to create a more realistic sound.
Buzzing
A signal-related descriptor in audio assessment: A zzz-like, undesirable sound typically in the low and midrange frequencies.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
Byte
Data word, consisting of a number of bits, normally 8.
Cc
See all in C
See all in C
Microphone Dictionary
Cc
C
1: The symbol for capacitance (see this).
2: The abbreviation for Celsius (see this).
3: The abbreviation for coulomb (see this).
c/n
In wireless transmission: Carrier to Noise Ratio.
c/s
See Cycles per Second.
Calibration
The process of measuring to determine the accuracy of the measurement chain. A microphone calibration provides the absolute sensitivity of the unit.
Calibrator, Acoustic
A device that produces a known sound pressure on a microphone in a sound level measurement system.
Camcorder
A contraction of the words camera and recorder; the recording medium and the camera are built together as a unit.
Canny
A timbre descriptor (bass range) in audio assessment.
The music sounds like it is being played in a can or tube. The sound is characterized by prominent and narrowband resonances in the midrange.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Capacitance
Capacitance is the ability of a component or circuit to collect and store energy in the form of an electrical charge.
Capacitor
A capacitor is an energy-storing device. It consists of two plates of conducting material. The conducting materials are sandwiched around an insulator made of, for instance, ceramic, film, glass, or air. (Hence the names ceramic condenser, film condenser, etc.). The insulator is also known as a dielectric, and it boosts a capacitor’s charging capacity.
In condenser microphones, the dielectric is air. One of the backplates and the diaphragm form the capacitor.
Capacitors and batteries both store energy. While batteries release energy gradually, capacitors discharge it quickly.
Capacitor Microphone
See Condenser Microphone.
Carbon Microphone
A microphone element that consists of two metal plates separated by granules of carbon. When one plate (the diaphragm) is vibrating, the carbon's resistance varies, modulating an electric current through the element. Earlier, widely used for telephones.
Cardioid Microphone
A microphone with a unidirectional characteristic that picks up sound in the front.
A waveform (typically a sine wave) whose frequency or amplitude is modulated by a signal. Like, for example, in wireless transmission (radio or wireless mics).
Cartridge
Special tape cassette with 1/4-inch tape earlier used for jingles, ads, etc., at radio stations. Format: mono, stereo or 8-track versions.
Cat #
Category of cables for Ethernet. The number describes quality. Higher numbers means higher quality:
Cat 5 enables bandwidth of 100 MHz.
Cat 5E (Enhanced Cat 5) enables bandwidth of 350 MHz.
Cat 6 enables bandwidth of 550-700 MHz. Cable run 50 m.
Cat 6A (Augmented Cat6) as Cat6, however cable run up to 100 m.
Cat 7 enables bandwidth of ≥700 MHz.
Cat 7A (augmented Cat7).
CC
See Compact Cassette.
CCIR
Comité Consultatif International pour la Radio (Consultative Committee on International Radio). Formed in 1927 to manage the international radio frequency spectrum and to develop standards for radio broadcast systems, primarily in Europe. In 1932, the CCIR merged with the International Telegraph Union (ITU) and several other organizations to become the International Telecommunication Union in 1934. In 1992, the CCIR became the ITU-R, the radio communications section of the ITU.
The CCIR Curve is a standardized weighting curve for the measurement of noise, for instance, in microphones. The standard was originally numbered in the CCIR system as CCIR 469-4 but is now maintained by the ITU and named ITU-R BS.468-4.
A unit for temperature. The behavior of water defines the scale: 0 °C: Point of water freezing; 100 °C: Point of water boiling. The scale is named after the Swedish scientist Anders Celsius.
Center Frequency
The arithmetic center of a constant bandwidth filter or the geometric center (midpoint on a logarithmic scale) of a constant percentage bandwidth filter.
Channel Packing
In wireless transmission: Methods to maximize the number of channels available within a given bandwidth of the radio wave spectrum, for instance, within the bandwidth of one designated tv-channel. The number of available channels varies from brand to brand: from 12 channels to 63 channels within one 8MHz frequency channel. Packing more channels is usually at the cost of other qualities.
Channel Separation
The attenuation of one channel appearing in neighboring channels.
Channel Spacing
In wireless transmission: The distance in frequency between each channel in a group of channels in a frequency band.
Channel Width
In wireless transmission: The RF-frequency span for a modulated channel.
Charge (Microphones)
An electric potential between back electrode and diaphragm that makes condenser microphones work. External voltage is applied to traditional condenser microphones. Electret microphones are pre-charged and will only need external supply for the built-in electronics.
Chest Voice
A term used within vocal music, especially in classical singing. However, the use of this term varies widely within vocal pedagogical circles and there is currently no one consistent opinion among vocal music professionals in regard to this term. It is not acoustically measurable. The term can be used in relation to the following:
• A particular part of the vocal range or type of vocal register
• A vocal resonance area
• A specific vocal timbre
[Source: Wikipedia].
Clapboard
A small board that displays information for each shot in a movie or documentary and is filmed at the beginning of a take. The board typically contains the working title, the names of the director, editor and director of photography, the scene and take numbers and the date and time.
On the top of the clapboard is a hinged wooden stick (called a clapstick or clapper) which is often clapped to provide audio/visual synchronization of the sound with the picture during editing. Electronic clappers and synchronization are also used instead of the old-fashioned clapboard. Also called Clapper. [Source: Filmsite.org]
Clarity
A transparency descriptor in audio assessment.
The impression of how clearly different elements in a scene can be spatially distinguished from each other.
A singer and a piano performing a duet in a dry acoustic, may be perceived as clear. When listening to a choir from the rear of the church, the sound of the individual singers may be unclear.
Scale applied in listening tests: Unclear - Clear
[Reference: Report ITU-R BS.2399-0]
Clean
A transparency descriptor in audio assessment.
It is easy to listen to music, which is timbral clear and distinct. Instruments and vocals are reproduced accurately and distinctly. The opposite of clean: dull, muddy.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Clean Sound
Atmospheric sound.
Clipped
A signal-related descriptor in audio assessment.
The harmonics are too pronounced and sharp.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Clipping
An electrical signal is clipped if the signal level exceeds the capabilities of the amplifier. It is a distortion of the signal.
Non-uniformity in off-axis frequency responses resulting in a distortion of the tonal quality of the source.
Comb Filter
A distortion produced by combining an electrical or acoustical signal with a delayed replica of itself. The result is a series of tops and dips across the frequency response that makes it look like a comb.
When using balanced lines, the induced electromagnetic noise is rejected due to the common mode, the fact that the impedance is exactly the same between each leader and ground (pin 2 to 1 and 3 to 1 in a 3-pin XLR connector). This is called common mode rejection.
Compact Cassette, CC
Registered name for the cassette developed by Philips with a 3.81 mm (0.15 in) audio tape.
Compander
A contraction of compressor and expander. A device that can perform both functions.
Complex tone
A tone that consists of more than a single frequency. See also Harmonic Overtones.
Component Frequency
Another term for harmonic or partial. Basically, a pure tone (perceptually) or sinusoid (mathematically).
Compressed
A signal-related descriptor in audio assessment.
Limited dynamic range leading to a lack of natural peaks. Dynamic compression may be heard as a pumping effect.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0].
Compression
Reduction of the dynamic range of recorded audio.
Compressor
A device or a plug-in that provides reduction of the dynamic range of recorded audio.
Condenser Microphone
A microphone in which the diaphragm is one plate of a capacitor. The capacitance of the microphone condenser is typically in the range of 10 – 50 pF.
The ability of a material to conduct electricity. It is the reciprocal of resistance and thus calculated as the current divided by the voltage (G=1/R=I/U). The unit in the SI system is Siemens. Formerly the unit Mho [Ʊ] applied (ohm spelled backward).
Consonant
1. In phonetics, a speech sound that is articulated with a complete or partial closure of the vocal tract (contrary to vowels). Examples are B, P, G, K, T. In non-tonal languages, consonants are essential for speech intelligibility.
2. In music, generally, consonant means pleasing tonality, having good harmony.
3. The name of a rock band.
A transducer that is mounted directly on the body of the musical instrument and picks up the mechanical vibrations of that instrument instead of the acoustical sound.
Content 0
Material or essence used for distribution by an operator.
Convolution Reverb
Convolution reverb is a software-based process used for digitally simulating the reverberation of a physical or virtual space. It is based on the mathematical convolution operation and uses a pre-recorded audio sample of the impulse response of the space being modeled. The impulse response is typically a recorded pistol shot, balloon popping or the like. Each recording describes the response in that specific position. The impulse response is then convolved with the incoming audio signal to be processed.
Core Audio
Core Audio is a driver protocol for digital audio in Apple's Mac OS X and IOS operating systems. It provides a low-latency and high-fidelity interface between a software application and sound card.
Corner Frequency
Transition frequency of a filter.
Corner Vowels
Vowels [a], [i], and [u]; vowels at the corner of the vowel triangle; they necessitate extreme placement of the tongue. [Source: National Center for Voice and Speech].
Coulomb
A unit of electric charge, equal to the quantity of electricity (electrons) transferred in one second by a current of one ampere. It takes approximately 6.24 * 1018 electrons to establish one coulomb of charge.
The condenser microphone is either internally charged (electret condenser microphone) or externally charged.
CPS
Cycles per Second (see this).
CRC
Cyclic Redundancy Check. Error correction.
Creaky Voice
A perceptual result of subharmonic or chaotic patterns in the glottal waveform; if a subharmonic is below about 70 Hz, creaky voice may be perceived as pulse register.
[Source: National Center of Voice and Speech].
Crest Factor
The term used to represent the ratio of the peak (crest) value to the RMS value of a waveform. For example, a sine wave has a crest factor of 1.4 (or 3 dB), since the peak value equals 1.414 times the RMS value. Music has a wide crest factor range of 4-10 (or 12-20 dB). This means that music peaks can be 12-20 dB higher than the RMS value, which is why headroom is so important in recording and audio design.
Critical Band
In human hearing, only those frequency components within a narrow band, called the critical band, will mask a given tone. Critical bandwidth varies with frequency but is usually between 1/6 and 1/3 octave. The ears act like a set of parallel filters, each with its own bandwidth.
Critical Distance
The distance from a sound source in a room at which the direct sound and the diffuse, reflected sound has the same level.
The process of gradually fading from one audio source to another. In the middle, both sources can be heard.
Crossover Frequency
In a loudspeaker with multiple radiators, the crossover frequency is the -3 dB point of the network dividing the signal energy.
Crosstalk
In audio equipment, crosstalk is any phenomenon by which a signal transmitted in one channel creates a audible/measurable portion in other channels.
Crystal Microphone
Crystals which exhibit the piezoelectric effect (see this) create voltages when they are deformed. A crystal microphone uses a thin strip of piezoelectric material attached to a diaphragm. The two sides of the crystal acquire opposite charges when the crystal is deflected by the movement of the diaphragm.
Cue
Audio or visual information that concerns timing or synchronization.
Cue Wheel
Control button for use with slow forwards and backwards winding with cueing.
Cupping
Holding one or two hands around the grid of a vocal microphone. This grip causes coloration of the frequency response. Applies in particular to beatboxers.
Term used in CVT (Complete Vocal Technique): Curbing is the half-metallic mode, meaning there is some metal in the notes. It is the 'mildest' of the metallic modes where the character is softer and not as powerful and distinct as Overdrive or Edge but still powerful compared to Neutral. The sound is often slightly plaintive and restrained.
Cutoff
The cutoff frequency of a filter. The frequency at which a filter begins to attenuate. Often defined by the attenuation being 3 dB at the frequency concerned.
CVT
Complete Vocal Technique. A singing technique developed by Cathrine Sadolin.
Cycles per Second (CPS or C/S)
Formerly used for the quantification of frequency, Hz.
A plug type that can be used, among other things, for the transfer of digital signals. The flange around the connector pins are D-shaped, hence the name.
DAC
See Digital-to-Analog Converter.
Damped waves
A wave in which the amplitude decreases over time (contrary to continuous wave). Example: The sound of a drum or a bell.
Damping
Removal of echoes and reverberation using sound absorbing materials.
Damping material
A material that absorbs, reduces or disperses sound waves to control reverberation.
See also: Absorber
Digital Audio Network Through Ethernet / AoE / AoIP. Initially developed by Audinate. Many third-party manufacturers support the protocol.
Dark - Bright
A timbral balance descriptor in audio assessment.
Denotes the balance between bass and treble.
Scale applied in listening tests:
• Dark: Excessive bass. Either loud bass or weak treble
• Neutral: Bass and treble are perceived equally loud, there is a balance in the reproduction. This also applies if both bass and treble are equally weak or if the bass and treble are both too loud. If it leads to prominent or soft midrange this is assessed by the Midrange strength
• Bright: Excessive treble. Either loud treble or weak bass
The cause for the sound being dark or light can be deduced from the assessments of Bass Strength and Treble Strength.
[Reference: Report ITU-R BS.2399-0]
DAT
Digital Audio Tape (-recorder). Digital tape format (cassette). Normally understood as R-DAT (Rotary head DAT) as opposed to S-DAT (Stationary head DAT), which never became a widespread format.
An acoustic measurement where an A-weighting band-pass filter is inserted in the measurement chain. The A-curve is specified by the IEC. It reduces frequencies below 1 kHz but slightly gains frequencies in the range of 1-4 kHz. This curve emulates the ear’s frequency sensitivity at low levels.
dB(C) or dBC
An acoustic measurement where a C-weighting band-pass filter is inserted in the measurement chain. The C-weighting curve is specified by the IEC. The corner frequencies (-3dB) are 31.5 Hz and 8 kHz respectively.
dBFS
Decibels, relative to full-scale sine wave (per AES17).
dBm
Logarithmic relation with a reference of 1 mW/600 Ω.
dBr
An abbreviation for decibels, relative. It usually refers to a reference level such as -20 dBFS or -14 dBFS. It is applied to indicate that the signal may contain values exceeding 0 dBFS.
dBTP
Decibels, true-peak relative to full scale (per ITU-R BS.1770 Annex 2).
dBu
Logarithmic ratio with a reference of 0.775 V.
dBV
Logarithmic ratio with a reference of 1 V.
DC
Direct Current (see this).
DC Coupling
The connection of a signal from one circuit to another in a manner that allows both AC and DC components to pass.
DC Offset
The change in input voltage required to produce zero output voltage when no signal is applied to a device. This is an unwanted phenomenon in audio; however, DC offset often occurs in inferior sound cards.
De-clipping
An algorithm designed to reconstruct audio signals which exhibit clipped waveforms. The reconstruction works best for digitally-clipped signals (signals exceeding 0 dBFS). The result is seldom beneficial if applying any filtering before the de-clipping process, as this may change the waveform.
De-emphasis
See Emphasis.
De-esser
Signal processing to reduce excess sibilance, typically in vocal recordings.
Decade
Ten times any quantity or frequency range. The frequency range of the human ear is about three decades.
Decay Rate
A measure of the decay of acoustical signals, expressed as a slope in dB/second. The rate at which a signal drops off.
Decca tree
A stereo microphone technique developed by Roy Wallace and Arthur Haddy at Decca Studios in London in the 1950s, most used for orchestral recordings. Originally, it used three cardioid microphones, but later switched to omnidirectional microphones (Neumann M50s). The mics are arranged in an upside-down “T” pattern. Two microphones are placed left and right approximately 2 m (6 ft) apart with the third placed in the center about 1 m (3 ft) in front, approximately 2.5-3 m (8-10 ft) up. This configuration produces a strong stereo image. It is sometimes called ABC Stereo.
[Source: Los Senderos Studio, Recording Studio Glossary]
Suitable restructuring of data, for example swapping bandwidth (sampling frequency) for bit depth.
DECT
Digital Enhanced Cordless Telecommunications. Originally for domestic cordless telephones. The allocated frequency band around 1.9 GHz is now available for license-free wireless microphone systems.
Delay
Time delay. (1) Electrical circuit that can delay a signal, in practice from fractions of a millisecond up to multiple seconds; used for sound effects. (2) Unwanted effect of time-consuming digital conversion, processing, etc.
See Latency.
Delta-Sigma Converter
Serial conversion at a high sampling frequency, where each bit specifies whether the current value of the signal is higher or lower than the prior one. After this process, this bit stream is converted to standard values, for example 16-bit format.
Depth
A spatial descriptor in audio assessment.
The radial extent of source, scene or ensemble from the listener (in any direction away from the listener).
A talker in a dry acoustic environment may be perceived as having little or no depth. A crowd in a stadium has depth. The sounds of the crowd are simultaneously occurring close to and far from the listener.
Scale applied in listening tests: Shallow - Deep.
[Reference: Report ITU-R BS.2399-0]
Detailed
A transparency descriptor in audio assessment.
A well-resolved sound, rich in detail. Instruments, voices etc. can easily be separated.
Music has many details, details that cannot be measured, details that give the music "soul". It may be small audible nuances: Breathing from a singer, fingers wandering across the guitar strings, the flaps from the clarinet, embouchure sound of the saxophone, the impact from the piano's hammers when they hit the strings, to name a few.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
DHCP
Dynamic Host Configuration Protocol, see this.
DI
1. Digital In, digital input.
2.Direct Injection, intermediate amplifier.
3.Directivity Index, directional index for acoustic transducers.
Dialnorm
An AC-3 metadata parameter, numerically equal to the absolute value of the dialog level carried in the AC-3 bit stream.
Dialog Level
1: In audio/AV production: The loudness, in LKFS units, of the anchor element (see this).
2: In multi-channels systems, the dialog level adjust is a level-setting of the center-channel, which usually carries the dialog.
In film, dialogue matching is a process to make secondary recordings of dialog (from lavaliers, plant mics, a dubbing studio, etc.) sound the same as the primary recordings (from overhead boom mic or the like). Izotope has introduced Dialog Matching as a plug-in for ProTools.
Diaphragm
The movable part in a microphone that reacts to the sound. Often also called the membrane.
Difference Frequency Distortion
Difference frequency distortion considers only the difference terms of intermodulation distortion. Such tones are not harmonically related and are therefore musically undesirable. It is a percentage of the signal amplitude.
Diffraction
The distortion of a wave front caused by the presence of an obstacle in the sound field. The scattering of radiation at an object smaller than one wavelength and the subsequent interference of the scattered wavefronts.
Diffuse Field Response
The diffuse field response is significantly different from the on-axis response and shows the microphone's tonal qualities when placed in a highly-reverberant environment with a large distance to the sound sources.
Concerning a state wherein an electrical signal has been converted to a series of impulses according to a specific code. The signal has come to exist in "tabular form".
The DAW was initially a dedicated computer-based system for recording, editing, and mixing audio. Today DAWs are software-based systems to be used with most standard IOS or Windows-controlled computers.
Digital snake
For PA/SR systems, the bus cable carrying digital audio signals between scene microphones and the mixer in the concert hall/venue.
Digital-to-Analog Converter (DAC)
The device that recreates an analog signal after being represented by digital values.
An electric charge driving the current – the electrons – in only one direction (contrary to Alternating Current, AC, which drives the current in both directions).
Direct radiator
A loudspeaker where the sound shoots directly from the front of the cabinet, as the vast majority of studio monitors.
Direct Sound
In acoustics, sound radiated from a sound source and not affected by reflections. In sound for film, the technique of recording sound simultaneously with the recording of the image.
Measure of the response of a microphone to sound incident from various angles or of the radiation pattern of a loudspeaker. The sensitivity (referred to as on-axis sensitivity) is plotted as a function of angle of incidence at various frequencies.
Also called "polar pattern".
The ratio of the mean-square pressure (or intensity) on the axis of a transducer at a certain distance to the mean-square pressure (or intensity) that a spherical source radiating the same power would produce at that point.
Directivity Index (DI)
Directivity factor expressed in dB (10*log(directivity factor)).
Mixing (of images). Corresponds to crossfade in audio.
Distance
A localization descriptor in audio assessment.
How far a sound source, ensemble or scene is perceived from the listener. Hearing a person talking close to a listener in a park may be perceived as near, whereas a person at a large distance may be perceived as far.
Scale applied in listening tests: Near – Far
[Reference: Report ITU-R BS.2399-0]
Distance Double Law
When you double the distance from a point source, the sound pressure is halved (reduced by 6 dB).
Distorted
A signal-related descriptor in audio assessment.
Additional and undesired sounds that add a sharpness to the reproduction.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Distortion
Any change in the waveform or harmonic content of an original signal as it passes through a device. The result of non-linearity within the device.
Amplifier that can distribute a signal to multiple inputs without the signal source becoming overloaded.
Dither
Noise added to a signal in the digital domain when reducing bit depth. The purpose is to reduce distortion at low levels. To further reduce audibility of the added noise commonly noise shaping is used.
Diversity
True Diversity or Receiver Switching: In wireless microphone transmission, the principle that one receiver contains two separate antennas and two separate receiver circuits. The signal from the receiver with the strongest reception is passed to the output.
Antenna Diversity or Antenna Switching: The receiver contains two antennas from which the strongest signal is passed to the receiver via a fixed interval switcher.
DivX
A brand name, usually referring to the DivX codec, which by applying MPEG-4 algorithms, provides compression of long videos to reduce their file sizes while keeping the video quality relatively high.
DO
Digital Out; digital output.
Do di petto
(Italian term in singing) C in chest.
Dolby E
An audio data-rate reduction technology designed for use in contribution and distribution that also conveys Dolby E metadata.
Doppler Effect (Doppler Shift)
The apparent upward shift in frequency of a sound as a noise source approaches the listener or the apparent downward shift when the noise source recedes (e.g. ambulance passing a bystander).
To automatically extract a stereo or mono mix from a higher-order immersive format system like 5.1, 7.1.4, or Dolby Atmos.
DPSK
See PSK.
DRC
Dynamic range control.
DRC Profile
A collection of parameters that describe how dynamic range control metadata is calculated.
Drop Frame
Variant of time code, where a frame is periodically skipped in order to preserve synchronization.
Drop-out
Short-duration loss of the signal on a tape due to faults in the tape's magnetic coating.
Dry Miking
See Close-miking.
DSB
Digital satellite broadcasting.
DSP
Digital signal processor. A circuit that can perform manipulation of data.
DTS
Digital Theater System. Digital sound system originally for movies. The sound information is stored on a CD-ROM, which is controlled by a time code on the film. Uses APT-X bit reduction.
Dubbing
Mix of one signal with another.
Dubbing Stage
In film, a dubbing stage is usually a studio facility that looks like a combination of a cinema and a recording studio. This is where the final decisions are executed regarding the sonic elements of the film. A dubbing stage gives the decision-makers the best possible representation of how all the audio and visual elements are working together in the context of how the film will be seen and heard. Often the dubbing stage is used for re-recording location dialogue. [Source: Filmsite.org]
Ducking
Automatic compression, for example when a speaker's insert dims the music signal.
Durability Factors
Important set of features for microphones. Includes how well the microphone withstands heat, cold, mechanical stress, dust, humidity, sweat, electromagnetic fields, etc.
A DHCP-server in the network provides the connected units with the network information they need to work.
Dynamic Microphone
A microphone with an electrodynamic transducer; either moving coil or ribbon microphone.
Dynamic Range
Range between the quietest and loudest levels a device can produce or detect. For a microphone or measuring system, it is normally specified as the range between the inherent noise level and a level leading to a specified amount of distortion.
A word created as an audio parallel to the visually based icon/iconography. An “earcon” is an easily recognizable sound used for messaging, i.e., in computers, smartphones. or household devices (I.e., the “ding” when the microwave has finished your popcorn or the “litter sound” when your computer’s waste bin empties.)
Early Decay Time (EDT)
In room acoustics, the first 10 dB of the decay after the sound has stopped.
A microphone setup developed by Eberhard Sengpiel of the Berlin University of the Arts. This setup is based on two cardioid microphones spaced 25 cm (9.8 inches) apart and at an angle of 90°. Similar techniques use other angle values, but 90° is considered easier to set up. The EBS technique can be categorized as a near-coincident design.
[Source: Los Senderos Studio, Recording Studio Glossary]
Eight-to-fourteen modulation. Digital modulation form, used for CDs among other things.
EFP
Electronic Field Production. The production form typically applied for drama and documentary produced outside the studio.
EFX
See Special Effects.
EIAJ
Electronic Industry Association of Japan. An interest organization in Japan that issues some norms.
Eigen Mike
An array microphone that Meyer and Agnello developed in 2003. It consists of 32 miniature microphones arranged on an 84 mm diameter rigid sphere. By processing the microphone signals, higher-order ambisonic directivity patterns can be obtained (up to 4th order).
Eigentone
(From German). 1. A tone that emanates from the resonance of a vibrating body or an acoustic space.
2. In film sound: Characteristic noise of a specific room. Sometimes called room tone.
Electret Microphone
A condenser microphone with a permanently charged membrane/back electrode. External voltage only needed for impedance conversion/built-in electronics.
An electronic or electrical product like a microphone must work as intended in its environment. The microphone should not generate electromagnetic disturbances, which may influence other products. Moreover, it should exhibit immunity to other equipment and systems' electromagnetic fields. Electromagnetic interference (EMI) should not occur.
A technique often used in analog transmission systems (wireless microphones, FM broadcast, etc.) or analog recording media (vinyl, tape, etc.) to enhance dynamic range by raising predominantly higher frequencies. De-emphasis is introduced on the receiving side.
The process of converting information (signal) into a coded form.
End-Addressed Microphone
If placing the microphone capsule at one end of a tube-shaped housing, the on-axis direction is in line with the tube. Also called "pencil microphone".
ENG
Electronic News Gathering. TV production of news based on electronic video camera as opposed to film camera.
Envelopment
A spatial descriptor in audio assessment.
Degree of being surrounded by a source, scene or ensemble. Typically, envelopment is associated with a scene.
Being surrounded by reverberation would be considered highly enveloping. Being surrounded by a large number of dry sources may also be highly enveloping. This may be heard when standing and listening to the rain hitting the pavement. Envelopment may occur with reverberation or other aspects of the scene such as applause in a concert hall, atmosphere or air conditioning (room tone). Holes (an absence of sound from a certain directions) in the reproduction would normally reduce envelopment.
Envelopment may be subdivided into horizontal and vertical envelopment.
Scale applied in listening tests: Scale: Not enveloping – Completely enveloping.
Epiglottis
A flap of cartilage that seals the entry-way to the larynx during swallowing and opens the entry-way during breathing
[Source: National Center of Voice and Speech].
Equal Loudness Contour
A contour representing a constant loudness for all audible frequencies. The contour with a sound pressure level of 40 dB at 1000 Hz is arbitrarily defined as the 40-phon contour.
Equalizer, Graphic
Electronic equipment for "equalizing." Built from a number of 1/1 octave or 1/3 octave band-pass filters that can each amplify or attenuate and used to obtain a desired frequency response.
Equalizer, Parametric
Electronic equipment for "equalizing". Constructed from a set of filters where the center frequency, bandwidth and amplification/attenuation can be adjusted independently for each filter.
Equalizing
1. The process that consists of modifying the frequency balance in the amplifier chain for the purpose of obtaining a flat frequency response, minimizing noise or achieving an artistic effect.
2. Equalization of nonlinearity (in frequency response).
Equivalent Noise Level
The equivalent noise level states the self-noise of the microphone either as an A-weighted RMS-level or as an ITU-weighted peak-level.
A computer network technology used in Local Area Network (LAN), Metropolitan Area Network (MAN), and Wide Area Network (WAN). Coax cables, twisted pairs, and fiber optics are applied. The bitrate is currently up to 400 Gbps (Gigabits per second).
ETSI
European Telecommunications Standards Institute. Publishes standards for wireless transmission, of which 300-422 is one: Allows a maximum RF channel bandwidth of 200 kHz.
Expander
1. Electronic equipment in which the output signal's dynamic range is increased in relation to that of the input signal.
2. Designation for a controllable synthesizer without a keyboard.
Ff
See all in F
See all in F
Microphone Dictionary
Ff
F
Farad, see this.
F/X
See Special Effects.
F0
(F zero) Fundamental frequency of a tone containing multiple harmonics. Mainly used within voice research.
Fade
A gradual change in the intensity of a sound. Fade in turns up the level. Fade out reduces the level to silence. Crossfade is the process of gradually fading from one audio source to another. Halfway through the crossfade, both sources can be heard.
Far End Audio
A term usually applied to networked audio. Network to loudspeakers.
Far Field
A region in free space at a much greater distance from a sound source than the linear dimensions of the source itself where the sound pressure decreases according to the inverse-square law (the sound pressure level decreases 6 dB with each doubling of distance from the source).
Farad is the SI-derived unit of electrical capacitance; the ability of a body to store an electrical charge. The unit is named after the English physicist Faraday.
FFT
Fast Fourier Transform. An efficient method of estimating the frequency spectrum of a signal.
File-based Scaling Device
A device used to apply an overall gain correction to audio content stored as files.
Filter
A device or algorithm for separating components of a signal based on its frequency. It allows components in one or more frequency bands to pass relatively unattenuated while attenuating components in other frequency bands.
Filter, Band Pass
A filter that passes all frequencies between a low-frequency cut-off point and a high-frequency cut-off point.
Filter, High-boost
A filter that amplifies frequencies above a specific frequency.
Filter, High-cut
A filter that attenuates frequencies above a specific cutoff frequency.
Filter, High-pass
A filter that passes all frequencies above a cutoff frequency but attenuates low-frequency components. They are used in instrumentation to eliminate low-frequency noise and to separate alternating components from direct (DC) components in a signal.
Filter, Low-cut
A filter that cuts off low-frequency signals below the cutoff frequency with a certain attenuation (roll off). In microphones, the filters are typically active below 80-300 Hz, and the slope is typically 6 or 12 dB/octave.
See also Filter, High-pass.
Filter, Low-pass
A filter that passes all frequencies below a cut-off frequency.
Filter, Notch
Narrow-band filter with very strong attenuation in a very narrow frequency range. Used to remove individual frequencies, for example hum.
Filter, Octave
Filter with a bandwidth of an octave.
Filter, Shelving
A type of filter that gives constant amplification or attenuation from the corner frequency.
Filter, Third-octave
A filter whose upper-to-lower pass band limits bear a ratio of 2 1/3, which corresponds to 23% of the center frequency.
FireWire
FireWire is a digital interface connection standard intended for peripheral devices. The capacity is around 3.2 Gbps; competing standards: Thunderbolt and USB.
First-Order Pattern
See 1st Order Pattern.
Flanging
Sound effect based upon the direct signal mixed together with itself using varying time delays. Originally made using a tape recorder, where the source reel is slowed down by a finger placed on the flange of the reel.
Fluctuating / Intermittent
A signal-related descriptor in audio assessment.
Noise with varying loudness and/or pauses.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
FM
Frequency modulation. Modulation principle in which a carrier wave is varied about its center frequency in proportion to the frequency of the modulating wave and where the oscillation of the carrier wave is proportional to the amplitude of the modulating wave.
Fold Back
The musicians on the scene have a need to be able to hear themselves and the others musicians in a quite specific manner. They are given a fold back or monitor loudspeaker, where the sound is specially mixed for this purpose.
Foley Artist
In the post-production and editing stage of a film's production, the foley artist (named after pioneer Jack Foley) creates or adds incidental sound effects/noises (e.g., footsteps, gunshots, kisses, fight-sounds, punches, storm noises, slamming doors, explosions, etc.) that are synchronized to the film to match its visual component. [Source: Filmsite.org]
Foreground Sounds
Sounds that are required or appreciation of the program. Typically presented through the front channels of a surround presentation, usually consisting of sounds made by objects or people shown in an accompanying picture. Dialogue can usually, but not always, be classified as foreground sound. Music is a foreground sound in music television, or music radio programs.
[Source: EBU Wiki - Technical - Louddrafting]
Formant
Voice: A resonance in the vocal tract. A given voice sound may contain several formats independent of the spoken vowels, named F1, F2, F3, etc.
Musical instrument: A resonance in the instrument. It gives the instrument its characteristic sound almost independent of the tone played.
Formant Bandwidth
The difference in frequency between the two half-power points (i.e., -3 dB with reference to the top point) on the slopes of the formant frequency.
Formant Tuning
In talking/singing: A boosting of vocal intensity when F0 (the fundamental frequency of the voice) or one of its harmonics coincides precisely with the formant frequency.
[Source: National Center of Voice and Speech].
Forwarding and Queuing for Time-Sensitive Streams (FQTSS)
A term that applies to the AVB (Audio Video Bridging) interface standard.
FQTSS
Abbreviation for Forwarding and Queuing for Time-Sensitive Streams. See this.
Frame
In video, an image. The smallest unit of a time code.
Frame Sync
Short for "frame synchronizer".
Free Field
An environment in which there are no reflective surfaces within the frequency region of interest and the sound is isotropic and homogenous.
The ratio of the output open-circuit voltage of a microphone to the free-field sound pressure in an undisturbed plane progressive wave. Frequency and angle of incidence must be specified.
Frequency
The number of cycles per second, measured in Hertz (Hz) or 1000 Hz=kHz. The human ear is able to detect frequencies from appr. 20 Hz to 20 kHz. In terms of musical practice, the frequency correspond to pitch. This table shows the fundamental frequency of each key on a grand piano.
Frequency Band
A limited frequency range.
AF (Audio Frequency): Typical bands applied in the audible frequency range are octaves or fractions of octaves. Some frequency bands are standardized by ISO and named after the center-frequency: The 1 kHz octave band includes the frequency range 707 Hz to 1.414 kHz.
RF: Radiowaves (3 kHz – 300 GHz) are divided into frequency ranges, bands, i.e., Long Wave (LW), Medium Wave (MW), Short Wave (SW), Very High Frequency (VHF), Ultra High-Frequency UHF), etc. Within each band, a number of channels can be defined as the television channels in the UHF range.
Frequency Range
The frequency range is also called the microphone "bandwidth".
Unlike the frequency response it is not represented by a graph but will give the sound engineer a rough indication of the microphone's tonal span and weather it will match the full span of the sound source.
The frequency range states the microphone's upper and lower limiting frequencies plus the tolerance field of the on-axis response in dB. If no tolerance field is indicated the frequency range is submitted as the -3dB points of the on-axis response.
Frequency Response
The frequency response of a microphone is the characteristic graph obtained by recording the level in dB of the output signal of the microphone, while the microphone is exposed to a certain acoustic field of pure sinusoidal tones with equal intensity. The frequency response gives important information about the tonal balance of the microphone under different acoustic conditions.
In digital (radio) transmission, a method for modulating a digital signal onto an analog carrier. For example, 4FSK modulates four frequencies on a carrier wave.
Frequency Weighting
Modification of the frequency spectrum of a signal by means of a filter with a conventional characteristic known as A, B, C or D, RLB, CCIR/ITU, etc.
A fricative is a consonant sound that is made when you squeeze air through a small hole or gap in your mouth. When these gaps are used, the fricatives are called sibilants.
See Sibilance
Speech sounds produced by turbulence in a constriction of the vocal tract, such as an "s" produced with the teeth.
[Source: National Center of Voice and Speech].
FSK
Frequency Shift Keying (see this).
Fukada Tree
The Fukada Tree is designed by the Japanese audio engineer Akira Fukada in 1997. It is a microphone array based on the Decca Tree, but with five cardioid microphones and two additional omnidirectional microphones as outriggers to blend in between the front and rear channels.
Full
A timbral balance descriptor in audio assessment.
If both low and high frequencies are well represented with good extension the sound is Full.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Fundamental Frequency
The lowest frequency of a vibrating system. The spectrum of a periodic signal will consist of a fundamental component at the reciprocal of the period and possibly a series of harmonics of this frequency.
Gg
See all in G
See all in G
Microphone Dictionary
Gg
G
1: Large room acoustics: G is the sound strength (or relative sound level). G is measured using a calibrated omnidirectional sound source and is the ratio in dB of the sound energy of the measured impulse response to that of the response measured at a distance of 10 m from the same sound source in a free field.
2: Abbreviation for the SI prefix giga (10^9). See this.
Gaffer
In film production: The chief or head electrician or supervisory lighting technician in the film/photography crew on a movie set. The gaffer is responsible for the design and execution of a production's lighting plan on the set. The gaffer's right-hand assistant is known as the best boy. Gaffer tape refers to multi-purpose, sticky and wide black or gray cloth tape, used to mark studio floors, to hold things together, etc. Gaffer tape is also known as duct tape. [Source: Filmsite.org]
Gain
Amplification (in a circuit).
Gain Structure
The signal levels at different stages of a mixing console or a chain of audio devices. I.e. microphone level, line level, instrument level.
Gate
See Noise Gate.
Gear
Encompasses all equipment.
Giga (G)
SI prefix giga (10^9) like in Ω (gigaohms). Or in data storage giga (2^30): 1 GB = 1,073,741,824 B. (See Numbers in audio).
Glitch
When a bit is skipped, it can lead to a little "crack" in the sound.
Glottal Stop
A transient sound caused by the sudden onset or offset of phonation.
[Source: National Center of Voice and Speech].
Glottis
The airspace between the vocal folds.
[Source: National Center of Voice and Speech].
Gobo
See Baffle.
Gooseneck
A flexible boom for microphones. Length: From few cm/inches to 1 m (3 ft)
GPI
General Purpose Interface.
Gradient Microphone
A microphone where the directivity is determined by the difference (gradient) between frontal and rear input to the membrane. All 1st order directional microphones have some gradient component. A pressure microphone (zero order) does not have a gradient component. See 1st Order Pattern.
Figure 1 Left microphone is a gradient type (inlet to both the front and rear of the diaphragm), and the right microphone is a pressure type (only admittance from one side of the diaphragm).
Granular Synthesis
A technique of assembling (small) segments of recorded sounds – called grains – into new sounds. In the process, parameters like the grains' duration, the starting point in the file, pitch, modulation, and spatial distribution can be controlled. Granular synthesizers are either dedicated hardware devices or plug-ins for other systems.
Graphic Equalizer
See Equalizer, Graphic.
Ground
In electrical engineering (and audio engineering), “ground” or “earth” is the reference point in an electrical circuit from which voltages are measured, a common return path for electric current or a direct physical connection to the earth (via a conductive rod driven into the ground).
In wiring for audio, a screen around circuitry or wires connected to the ground shields from electrical/electromagnetic noise.
In electricity supply (mains installations), the ground wire provides an alternating route for current to flow back to the ground if there is a fault in the wiring system.
Groundplane Antenna
A antenna with one director, vertical quarter-wave element, and three reflectors at 120°.
Group delay
Digital processing takes time. Group delay is the delay over the complete frequency range observed and should stay constant at all frequencies. If the frequencies are delayed differently, it is called phase delay.
Hh
See all in H
See all in H
Microphone Dictionary
Hh
Haas Effect
Also called the precedence effect or principle of first arrival. If similar sounds arrive at the ear within approximately 35 ms, the sound's apparent direction is that of the direct sound. The auditory apparatus integrates delayed sounds if they fall on the ear within 20-40 ms of the direct sound. The level of the delayed components contributes to the apparent level of the sound and may be accompanied by a change in the character (timbre) of the sound.
The two frequencies on opposite sides of a resonant peak (or pass-band) where the power transmitted by a filter is half of its value at the peak (-3 dB re the top of the resonant peak).
Hamasaki Square
Microphone aray designed by the Japanese sound engineer Kimio Hamasaki. The Hamasaki Square is designed for capturing the ambient/diffuse part of a surround sound recording. It is a four-mic square with 1.8-2 m (5.9-6.6 ft.) between the figure-of-eight microphones, which are routed to left, right, left surround, and right surround at an appropriate level compared to the front array. The figure-of-eight microphones are pointed with their in-phase sensitive directions against the sides and with their nulls to the direct sound.
Compared to other systems for ambiance recording, this system is the least sensitive regarding the distance between the main array and the ambiance array.
Handling Noise
The sensitivity of a microphone to movement and shock. Expressed as an equivalent sound pressure level.
Harmonic
A discrete sinusoidal (pure-tone) component whose frequency is an integer multiple of the fundamental frequency of the wave. If a component has a frequency twice that of the fundamental, it is called the second harmonic, etc.
A standard for transmitting ultra-high-definition video and audio, Ethernet, control signals, USB and up to 100 watts of electrical power over one long-distance cable (Cat 6 or higher).
HDMI
Abbreviation for High-Definition Multimedia Interface. An interface standard for audio and pictures exchange over shorter distances (usually max 15 m/45-foot cable). Two connectors are dedicated to physical connections within the format.
Head Related Stereo
Stereo techniques using human interaural geometry as a model for the microphone set-up. Head related stereo is a generic term for a lot of different stereo techniques using both difference-in-time and difference-in-intensity stereo with microphone spacing and microphone off-axis attenuation related to the distance between the human ears and the shadow effect of the human head. Among the more standardized head related stereo techniques are ORTF stereo and DIN stereo.
A term used within vocal music, especially in classical singing. However, the use of this term varies widely within vocal pedagogical circles and there is currently no one consistent opinion among vocal music professionals in regard to this term. It is not acoustically measurable. The term can be used in relation to the following:
• A particular part of the vocal range or type of vocal register
• A vocal resonance area
• A specific vocal timbre
[Source: Wikipedia].
Headroom
Overload reserve. The amount of signal above nominal level that can be permitted before overloading arises with distortion as a consequence.
Hearing Level
A measured threshold of hearing at a specified frequency expressed in decibels relative to a specified standard of normal hearing. The deviation in decibels of an individual’s threshold from the zero reference of an audiometer.
Hertz, Hz
A unit of frequency measurement representing cycles per second.
Hexaphonie
A 6-channel format for picking up a sound sphere; developed by Madeleine Sola and Daniel Torsière at Radio France in the 1970s.
The format consists of a top layer triangle of three cardioid microphones spaced 35 cm and angled 120° relative to each other. In addition, a bottom layer spaced 35 cm below the top layer, consists of three cardioid microphones also arranged in a triangle like the upper layer. However, the bottom layer is rotated by 60° relative to the top layer. For the reproduction, each channel feeds one loudspeaker arranged in a similar configuration as the microphones.
HF
High frequency.
High-boost Filter
A filter that amplifies frequencies above a specific frequency.
High-cut Filter
A filter that attenuates frequencies above a specific cut-off frequency.
High-Pass Filter
A filter that passes all frequencies above a cutoff frequency but attenuates low-frequency components.They are used in instrumentation to eliminate low-frequency noise and to separate alternating components from direct (DC) components in a signal.
Higher-Order Ambisonics (HOA)
The Higher-Order Ambisonics is a further development from Ambisonics, a recording format based on the soundfield microphone providing A-format or B-format signals (See A-format, B-format and Soundfield Microphone).
Higher order means that the microphones involved are of an order different from 0 or 1st order microphones (see 1st Order Pattern.
A signal-related descriptor in audio assessment.
A noise-like sizzling sound, like the sound of bacon in a frying pan.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
HOA
Higher Order Ambisonics (see this).
Homogeneous
A timbral balance descriptor in audio assessment.
Denotes to which degree the different frequency ranges (bass, midrange and treble) are coherent, continuous and balanced without gaps between them. That there are seamless transitions between the tone ranges.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
House Sync
Sync signal that is distributed (in-house) so all digital devices can run at the same speed.
Hum Bucking
Hum bucking is a method to reduce induced electromagnetic noise (hum) in a dynamic microphone. The principle is to add a coil in series with the microphone's moving coil. This additional coil is oriented like the voice coil but mounted outside the magnetic system and reversely wound. This provides cancellation of external stray fields from powerlines, induction loops, etc.
Humming
A signal-related descriptor in audio assessment.
Low-frequency noise with tonal components.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
HVAC noise
Heating, ventilation and air conditioning noise. Used in connection with requirements concerning noise in control rooms, cinemas, etc.
Another expression for wide cardioid (or subcardioid).
Hz
See Hertz.
Ii
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Microphone Dictionary
Ii
iCheck
Integrity check. Reveals if the signal is spatially compromised, e.g., because of data reduction, such as MP3 or AAC encoded at too low a bit rate.
IEC
International Electrotechnical Commission. A standardization commission. The IEC has issued the most crucial measurement standard regarding microphones, IEC 60.268 Sound system equipment – Part 4: Microphones.
Institute of Electrical and Electronics Engineers. Interest organization with recognized standardization groups. Stands among other things for Essential Ethernet Standards (IEEE 802-3).
IETF
Internet Engineering Task Force. An interest group that also develops standards and recommendations.
IGMP
Internet Group Management Protocol. A multicast protocol that ensures that individual data packets are routed directly to the addresses for which they are intended.
IM
Intermodulation (see this).
Immersive Audio
Audio that generates immersion. Earlier, the expression “surround sound” was used; however, now immersive audio encompasses all sorts of audio formats that envelops the listener.
Impedance
Impedance is the complex load or complex input/output characteristics. The term indicates that the input- or output resistance of a circuit is not necessarily constant with frequency.
Matching the impedance of an input with the impedance of an input. When matched, maximum power is transferred from one circuit to the other. Impedance matching is mostly relevant for RF (transmitter-antenna and antenna-receiver) and electrical-coupled digital interfaces (like AES3 and the like). The long run of AF-cables, however, also takes advantage of impedance matching.
Impulse Response
The response of a system to a unit impulse. The Fourier transform of the impulse response is the frequency response.
See Transient.
In-Band pink noise
Filtered noise used for test purposes, which could be 20 Hz to 80 Hz for a subwoofer, or 250 Hz to 2.5 kHz for the main system.
In-Phase
Two periodic waves reaching peaks and going through zero at the same instant are said to be in phase.
The property that an electrical current is produced in a conductor when it is exposed to a varying magnetic field.
Inductor
Coil wound on an iron core.
Infrasound
Sound at frequencies below the audible range, i.e. below about 16-20 Hz.
Ingress Protection Code (IPxxyz)
This code clarifies and rates the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact and water. The code is found in the IEC standard 60529. The code is constructed from digits and letters: Code letters First characteristic numeral: Solid particle protection Second digit: Liquid ingress protection IP (International Protection) Single numeral: 0–6 or letter X Single numeral: 0–8 or letter X Mandatory Mandatory Mandatory DPA´s 6000 Series Subminiature Microphones conform to IP58, which means:
5: Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment.
8: Immersion, 1 meter (3 ft 3 in) or more depth. The equipment is suitable for continuous immersion in water under conditions which shall be specified by the manufacturer. However, with certain types of equipment, it can mean that water can enter but only in such a manner that it produces no harmful effects. The test depth and duration is expected to be greater than the requirements for IPx7, and other environmental effects may be added, such as temperature cycling before immersion.
Depth specified by the manufacturer, generally up to 3 meters (9.8 ft)
Inherent Noise
Noise that is internally generated in a system in the absence of any excitation. For a microphone, usually expressed as an equivalent sound pressure level which would produce the same output voltage as the noise voltage. Also called self-noise.
This occurs when two or more frequencies are supplied to a non-linear system. The spectrum at the output of the non-linear device will, in addition to the original signal, also contain the sum and difference of the input signals along with their harmonics.
Internality
An environment descriptor in audio assessment.
The distinctness to which a sound source, ensemble or scene is perceived inside the head. Distinctly internal means that a sound is unambiguously perceived within the head. Distinct external means that a sound is unambiguous perceived outside the head. If it is ambiguous whether the sound is perceived to be inside or outside of the head, the internality is Indistinct.
A dry sample played equally to both ears over headphone may be perceived inside the head. Naturally occurring sounds are generally perceived externally.
Scale applied in listening tests: Distinctly internal- Indistinct - Distinctly external
[Reference: Report ITU-R BS.2399-0]
Internet protocol (IP)
That part of a network-based system, that describes the structure.
Interpolation
Computation of intermediate values in relation to fixed values (for example, values between two samples).
Interstitial
In broadcast: Name for a short-form program with a duration typical less than 60 sec.
Inverse Square Law
A description of the acoustic wave behavior in which the mean-square pressure varies inversely with the square of the distance from the source. This behavior occurs in free-field situations where the sound pressure level decreases 6 dB with each doubling of distance from the source.
IP
1 Internet Protocol (see this). 2 Ingress Protection (see Ingress Protection Code)
ips
Inches per second.
IPv4
Present standard for Internet Protocol. Limited by the still growing demand for unique IP-addresses which is beyond what this standard can deliver.
IPv6
A revised standard that provides far more unique IP-addresses compared to IPv4.
IR
1. Infrared (light). Frequency range approximately 10^12 to 10^14 Hz. IR light is used as a control signal in remote control units.
2. Impulse Response. The impulse response of a room contains the acoustic information of that room in the position where measured. Impulse response of rooms also applies to convolutional reverbs which generates reverb of actual rooms. Further, the impulse response of the microphones is measured. This is a tool used in microphone development, however, seldom published as the results from different brands are hardly comparable.
ISO
International Standards Organization; the international organization for standardization.
Isolation
Resistance to the transmission of sound by materials and structures.
ISRC
International Standard Recording Code. Information about the country of origin, the owner, the year of recording and the serial number of a recording encoded on compact disc.
ITDG
Initial Time Delay Gap (see this).
ITU
International Telecommunication Union.
Jj
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Microphone Dictionary
Jj
Jack Plug
One-legged connector with two or three contacts. Normal dimensions are 6 / 3.5 / 2.5 mm (.24 / .14 / .1 in).
Jack-bay
A patch panel with jacks that are used to make connections between different devices easy to establish.
Jam Sync
Method for recording new time codes from a source tape.
Jitter
Expresses that the sample timing in a digital stream deviates from the fixed rate. Jitter is measured in seconds (typical ns or ps). Jitter causes noise in the signal reproduced. The worst kind of jitter is sampling jitter, as this cannot be corrected later. To some degree, transmission jitter can be compensated for.
Abbreviation for the SI prefix kilo (10^3). See this.
K-weighting
The K-weighting applies to the loudness measurement of program material. Each channel passes this filter before calculating the summed Leq (equivalent level, see Leq.
Figure 1 Response of the K-weighting function.
kbps or kb/s
Kilobits per second.
kHz, Kiloherz
One thousand hertz.
See Hertz.
kilo
SI prefix kilo (10^3) like in kΩ (kiloohms). Or in data storage kilo (2^10): 1 kB = 1024 B. (See Numbers in audio).
Ll
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Microphone Dictionary
Ll
L-Cut
A digital film editing term, also known as a split edit, J-cut or delayed edit. It refers to a transitional edit in which the audio and video edit do not start at the same time; the audio starts before (or after) the picture cut. [Source: Filmsite.org]
LAN
Local Area Network. Typically Ethernet-based with Cat5/6 cabling and RJ45-connectors.
Lapel Mic
Another name for Lavalier Microphone (see this).
Larsen Effect
Acoustic feedback in electroacoustic systems, and also known as howl or just feed. The effect occurs when there is positive feedback (gain >1) from a loudspeaker to a microphone. This effect may also occur between an induction loop and a dynamic microphone.
The effect is named after the Danish physicist Søren Absalon Larsen (1871-1957).
Larynx
An organ of the body situated in the neck, which houses the vocal folds.
Laser Microphone
A microphone based on the optical reflections of a laser beam when hitting a vibrating object, like a loudspeaker membrane or window glass.The time variance of the reflected signal is demodulated as audio.
Latency
Delay due to processing.
Lav Mic
Short for Lavalier Microphone (see this).
Lavalier Microphone
A microphone for speech that is attached to the clothing or worn around the neck. Lavalier originally means a necklace and refers to a microphone placement similar to that.
The first wave front falling on the ear determines the perceived direction of the sound.
Layback
A post-production technique where audio is rejoined with the associated video after editing, mixing or "sweetening".
LDC
Large Diaphragm Condenser (microphone). Often understood as microphones larger than ½ inch (1.27 cm) or side-address, large membrane condensers.
LED
Light-emitting diode.
Leq
Equivalent continuous sound pressure level.
Leslie Effect
The Leslie Effect is based on the sound of a loudspeaker cabinet containing a rotary reflector above a fixed loudspeaker unit and a rotating horn assembly that together creates a swirling and pitch-shifting sound. Further, the speed of rotation can be shifted between a slow and a faster mode.
The Leslie cabinet is named after the inventor, the American audio engineer Donald James Leslie (1911-2004), who in the 1940s designed this cabinet in his search for enhancement of the sound of the Hammond (B3) organ.
LF
Also known as Low Frequency.
Most often, LF is used to name oscillations in the lower part of the audible frequency spectrum (< 200 Hz). However, LF describes the complete audible frequency (AF) range in other contexts.
LF Equalizing Tube/Vent
A pressure microphone, in principle, consists of a diaphragm in front of a closed chamber. A small housing hole (capillary tube) allows for pressure equalization to prevent the microphones from recording the static pressure or extremely low frequencies. This small hole, or leak, is sometimes designed as a small-diameter tube or hose. In some cases (miniature microphones), the hole is cut in the diaphragm.
LFE
Low Frequency Effects, see this.
Limiter
A signal-processing unit that attenuates the output when the input exceeds a given threshold. This provides a fixed maximum output level.
Line Driver
A unit used to transform high impedance (and eventually unbalanced) source lines (e.g. guitar pickup) to balanced lines that can run in long cables.
Line Level
The voltage that the signals are amplified up to (for example, in the mixer) before they are routed to an output amplifier (or transmitter). In analog audio, the level between devices in the range of 0.3-3 volt. (To be distinguished from microphone level, which typically is in the range of 1-100 mV.
Line Spectrum
A spectrum that contains discrete (line) frequencies only. See also FFT.
Linear conversion
In digital audio: When each quantization step has the same size and the sampling frequency is constant.
Linear Phase Response
The phase is constant with frequency through the device or circuit.
Linear Pulse Code Modulation (LPCM)
A method for the modulation of audio into a digital and lossless (linear) format.
Linear Quantization
In digital recording: Equal-sized steps used for the definition of the individual samples.
Synchronization between mouth movement and the audible words when reproduced from film or video. Max off-sync allowed according to the standard ITU 1970 is -40 ms/+140 ms. However, a typical acceptance range is -0/+40 ms.
LKFS
LKFS is an acronym that stands for "Loudness, K-weighted, relative to Full Scale." A Loudness measure intended for digital audio programs, both audio-only and audio/video. See also K-weighting. LKFS is equal to LUFS.
The input of a microphone amplifier, mixer, etc. Acts as a load to the microphone output. Even the cable should be regarded as a load. The size of the load should be five to ten times the output impedance of the microphone.
Localizability
An environment descriptor in audio assessment.
The degree of precision to which the position and extent of a source or ensemble can be identified. This attribute is typically associated with sources or ensembles, rather than scenes. For a spatially imprecise sound, the listener may be unable to identify the position (and extent) of the source or ensemble for a spatially precise sound, the listener can confidently state the position and extent of the source or ensemble.
A clap in a dry environment may be spatially precise. Listening to rain fall in a forest maybe spatially imprecise.
Scale applied in listening tests: Imprecise – Precise
[Reference: Report ITU-R BS.2399-0]
Locate
To find a specific position, for example on a track, digital or analog.
Location Sound
Background sound on location, usually recorded separately for later adding to the final mix. See also Buzz Track.
Lombard Effect
The Lombard effect is an involuntary tendency for a speaker to increase his or her vocal effort to enhance audibility when speaking in a loud, noisy environment. Changes include not only loudness but other effects, such as pitch, rate, and duration of syllables. The reflex is also known as the Lombard reflex.
The reflex was discovered and described in 1909 by French scientist Étienne Lombard (1869-1920). It also exists in nature, i.e., among birds.
Long-form Content
Show or program related material or essence. The typical duration is greater than approximately two to three minutes.
Longitudinal
Lengthwise.
Looping
1. Infinite repeating of an (audio) sequence.
2. In film: The process in which dialogue is re-recorded by actors in the studio during post-production, matching the actor's voice to lip movements on screen (ADR).
Lossless compression
A bit-compression format that recovers all the original data from the compressed version.
Lossy Compression
A digital format that applies bit-compression and that cannot recover all of its original data from the compressed version. Supposedly some of what is usually recorded before compression is imperceptible, with the louder sounds masking the softer ones. Most systems utilize psychoacoustic models for the compression scheme.
Loudness Level
1. In acoustics: measured in phons it is numerically equal to the median sound pressure level (dB) of a free progressive 1000 Hz wave presented to listeners facing the source, which in a number of trials is judged by the listeners to be equally loud. Loudness level can be calculated according to ISO 532B.
2. In audio production: measured in loudness units (LU) according to ITU BS.1770.
A filter that cuts off low frequency signals below the cut-off frequency with a certain attenuation (roll off). In microphones, the filters are typically active below 80-300 Hz, and the slope is typically 6 or 12 dB/octave.
See High Pass.
Low-Frequency Effects
It is a particular recording channel containing 5 Hz to 120 Hz information primarily intended for special effects such as movie explosions. It applies to immersive multichannel systems like 5.1 or higher. The LFE channel has an additional 10 dB of headroom to accommodate the required level.
Low-Pass Filter
A filter that passes signals below the cut-off frequency and attenuates the signal above that frequency. An anti-aliasing filter in a digital system is an example of a low-pass filter with a very steep roll off.
Lower Limiting Frequency (-3dB point)
The lower frequency at which the frequency response of a pressure microphone has fallen by 3dB. Determined by the venting system which equalises the static pressure difference between the inside and outside of the cartridge.
LPCM
Linear Pulse Code Modulation (see this).
LR
1: In audio: Left/Right. 2: In wireless transmission: Long Range.
LTC
Longitudinal Time Code. The time code that is recorded on a tape's longitudinal track.
LU / LUFS
Loudness Unit / Loudness Unit re Full Scale. LUFS is equal to LKFS. A weighted measure that applies to program metering defined by the standard EBU R128. Based on the standard ITU BS.1770. K-weighting (see this) is applied in these standards.
Mm
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Microphone Dictionary
Mm
m
Abbreviation for the SI prefix milli (one-thousands, 10^-3). See this.
MAC
1 Media Access Control is a unique address for a unit applied in a (digital) network.
2 Name of popular computer
MADI
Multichannel Audio Digital Interface also known as AES10. An interface standard where up to 64 audio channels can be transferred serially on a cable, coax or optical. NRZI encoding, 125 Mbps.
Magnitude
The size of a signal.
Main Lobe
An expression related to the directivity pattern of antennas and microphones. The main lobe shows the sensitivity versus angle to signals coming from the front.
Antennas and microphones may also have a back lobe and side lobes.
Mark
Clapping the sticks to synchronize the sound and the picture.
Masking
The process by which the threshold of audibility of one sound is raised by the presence of another (masking) sound.
Matching (of Microphones)
Ensuring that all microphones in a stereo or a surround microphone kit perform to the exact same specifications.
A device that can mix and distribute signals. An MS matrix will transform MS to LR or vice versa.
Max SPL
A specification of microphones. DPA specifies a microphones' maximum peak-SPL when the output reaches a THD (Total Harmonic Distortion) of 10%. This specification indicates that the microphone delivers an increased signal already after the 1 % THD is passed. This parameter is also called Overload SPL.
In statistics, the squared difference between a data set's actual and expected values is averaged over the number of values. MSE is a standard test describing the quality of an estimator.
Measured Loudness
The magnitude of an audio signal when measured with equipment that implements the algorithm specified by ITU-R BS.1770/EBU R-128. It is an approximation of perceived loudness.
MEMS is an abbreviation for Micro-Electro-Mechanical-Systems. These microphones are generally manufactured from a processed slice of silicon. As the microphones are small and cheap, they are widely used as built-in transducers for mobile phones and other smart devices.
MEMS microphones have not reached the sound quality of electret microphones, not even the miniatures. The self-noise and the distortion in MEMS are higher compared to typical miniature electret microphones.
Meridian Lossless Packing, MLP
This data compression technique is designed especially for high-quality (96 kHz/24 bit) audio data. MLP differs from other significant methods because no significant data is thrown away. It is comparable to the Zip’ing of a data file.
Messa di voice (Italian)
(Italian term in singing): Placing of the voice; singing a crescendo-decrescendo with a well-placed voice.
META data
Additional data that goes with the core data of a file. In the case of a sound file, various schemes for these data exist. I.e., ID3, to be incorporated in wav-files. The information is specially designed for music distribution and comprises data about the artist, the album, and even graphics.
Metallic
In audio, sound production: Often, the perception of a metallic sound relates to comb filtering, where the signal is slightly delayed (ms) and added to itself. Other times the perceived metallic sound is caused by high-frequency resonances.
In voice recording: Typically, metallic voice occurs when increasing higher formants (F3-F4) in the voice spectrum. In singing, this is a parameter used to vary the impression of the voice.
Metaverse
The Metaverse is a digital copy of the real universe.
Meter
Designation for a measurement instrument for the control of signal levels.
Micro (µ)
SI prefix micro (Greek letter µ) for a factor of one millionth, 10^-6, like in µm (micrometer).
Microphone Array
See Array Microphones.
Microphone Level
The voltage output range of microphones with normal sensitivity, usually 1 mV – 50 mV. Microphones, however, may produce a voltage in the range of volts.
Microsoft Multimedia Environment, MME
MME is a native Windows audio driver protocol. The MME applies to most built-in audio cards, and the other way around, most PC audio software supports it.
Middle (or Mixed) Voice
The mixture between chest voice and falsetto; another term for "Head Voice" in singing.
[Source: National Center of Voice and Speech].
MIDI
Musical Instrument Digital Interface. A standard that defines and recommends hardware and procedures for control and communication between a controller and one or more MIDI-equipped musical instruments.
Midrange Strength
A timbre descriptor in audio equipment or recording assessment.
The relative level of the midrange, i.e., the middle frequencies, e.g., sopranos, trumpets, violins and xylophones. Not to be confused with Canny which represents prominent narrow frequency ranges (resonances) in the midrange.
Scale applied in listening tests: Soft – Loud
[Reference: Report ITU-R BS.2399-0]
Milli (m)
SI prefix m (10^-3) like in mV (millivolt). (See Numbers in audio).
MIPS
Million Instructions per Second. Quantitative specifications for (audio) processors.
Mix (Mixing)
The electrical combination of different audio sources. In film: The combination of dialogue, music, and sound effects. In music production: The combination of the sound from physical or electronic music instruments, vocals and effects. In the mix, many sources are balanced to the number of tracks adequate for the delivery format (mono, stereo or multi-channel).
Mixer
The engineer that performs the sound mixing.
Mixing Level
Indication of the absolute sound pressure level calibration of the mixing studio that produced the content.
MKV
MKV files are multimedia container formats. An MKV container can incorporate audio, video and subtitles in a single file, even if the elements apply different types of encoding. For instance, it is possible to have MKV files containing h.264 video and AAC audio simultaneously.
MLP
Meridian Lossless Packing, see this.
MMAD
Multichannel Microphone Array Design, see this.
MME
Microsoft Multimedia Environment (see this).
Mode
1. A room resonance. Axial modes in rectangular rooms are associated with pairs of parallel walls. Tangential modes involve four room surfaces and oblique modes all six surfaces. Their effect is greatest at low frequencies and in small rooms.
2. A specific setting for a device (like record mode, sleep mode, etc.)
Modulation
An analog process by which the characteristic properties of a wave (the modulating wave) are mixed into another wave (the carrier wave).
Modulation Noise
Noise in the signal chain that varies with the signal strength. Particularly a problem with audio tape recorders.
MOL
Maximum Output Level. For tapes, the highest attainable output.
Monitor
A control or monitoring device; in this context, a loudspeaker for the assessment of recording quality.
Mono
Signal in a single channel.
Mono Compatible
A stereo signal, if no significant loss of level and no coloration (comb filtering) occur when summing the channels to one mono signal.
A nickname for a Boundary Layer Microphone (see this).
MPEG
Motion Picture Experts Group. Standardization organization that sets standards for techniques such as digital audio compression.
MPX
Multiplex filter for removing an FM radio's stereo pilot tone.
MS Recording
A stereo recording technique using M (mid) and S (side) signals basically from one cardioid and one figure-8 microphone. To obtain L/R format the signals are processed like this: L = M + S, R = M - S.
Procedures to define microphone arrays for immersive recordings depending on mrecording space and microphone characteristics. Based on studies by te Scottish sound engineer, recording specialist, and lecturer, Michael Williams.
mV
Millivolt, 1/1000 V.
MVPD
Multichannel Video Programming Distributor. Includes DBS service operators, local cable system operators and cable multiple system operators.
Nn
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Microphone Dictionary
Nn
n
Abbreviation for the SI prefix nano (10^-9). See this.
N
See Newton.
NAB or NARTB
National Association of Radio and Television Broadcasters. American standardization organization.
NAG
Needed Acoustic Gain. In live sound reinforcement, the amount of gain in dB required by the sound system to achieve an equivalent sound level at the listener farthest from the stage equal to the level the nearest listener would hear without reinforcement.
Nano (n)
The SI prefix for a factor of one billionth, 10^-9, like in nF (nano farad).
Nanotechnology
Nanotechnology is science, engineering, and technology conducted at the nanoscale, about 1 to 100 nanometers. For example, in microphone manufacturing, treatment of components may apply for better performance and higher resistance to environmental factors by using nanotechnology.
Narration
The telling of a story, and the supplemental information given to the film audience, by an off-screen voice. Sometimes the narrator is a character in the film, who provides information in a flashback.
Narrow-Band Spectra
Spectra that have been measured using a narrow frequency bandwidth.
Nasal
A timbre descriptor (midrange) in audio equipment or recording assessment.
A closed sound with pronounced midrange. Gives the impression corresponding to vocalists singing through the nose (nasal).
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Native
1: Software that runs on a computer operating system that does not require additional hardware or software.
2: A host-based plug-in, i.e., the software uses the computer processor rather than a separate dedicated DSP.
Natural
A transparency descriptor in audio assessment.
Sounds reproduced with high fidelity. Acoustic instruments, voices and sounds that sound like they do in reality. The sound is similar to the listener's expectation to the original sound without any timbral or spatial coloration or distortion: "Nothing added – nothing missing". The soundstage is clear in space and brings you close to the perceived original sound experience.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Natural Frequency
The frequency at which a system will vibrate when set into free vibration. The frequency of oscillation of the free vibration of a system if no damping were present.
NBC
Non-backward compatible.
Near Field
That part of a sound file, usually within about two wavelengths from a noise source, where there is no simple relationship between sound level and distance.
Special signal processing unit whose output signal is 0 until the input signal exceeds a specific, preset value.
Noise Shaping
A special technique providing frequency weighting of dither used in connection with reducing high resolution digital audio to a lower bit format.
NOS
Nederlandse Omroep Stichting (Dutch Broadcasting Foundation). A microphone setup for stereo recording with two cardioid microphones. Distance between microphones: 30 cm. Angle between microphones: 90 degrees.
A filter to reduce a very narrow frequency band by a steep dip.
NR
Noise Reduction.
NRZ
Non-return to Zero.
nWb
Nanoweber = 10-9 weber.
See Weber.
Oo
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Microphone Dictionary
Oo
OBA
Object Based Audio. An audio object (i.e., a sound effect, the sound of a vehicle, an animal, etc.) is placed independently of recording channels to obtain the best position possible when reproduced with the system available. In audio production, the application of object-based audio has taken over from conventional channel-based audio. Dolby Atmos is an example of OBA.
A recording and reproduction format involving eight microphones distributed at equal distances on a horizontal circle. Reproduced by eight loudspeakers.
Octave
A range of frequencies whose upper frequency limit is twice that of its lower frequency limit. For example, the 1000 hertz octave band contains noise energy at all frequencies from 707 to 1414 hertz. In acoustical measurements, sound pressure level is often measured in octave bands and the center frequencies of these bands are defined by ISO and ANSI.
Octave Filter
A filter whose upper-to-lower pass band limit bears a ratio of 2. Is is best centered at one of the preferred frequencies given in ISO R266. Octave filters are used to make a real-time frequency analysis. These filters are called constant percentage bandwidth (CPB) filters. Octave filters can be divided into 1/3-, 1/12- or 1/24-octave filters, depending on the required resolution.
Off-axis Response
Off-axis responses are normally submitted for directional microphones only. Linear off-axis qualities on directional microphones are extremely difficult to obtain. Therefore it is important to pass on information about the off-axis responses to the sound engineer, so he can compare the acoustic quality of different microphone types.
The on-axis response is normally just referred to as the microphone's frequency response and will give information about the product's tonal behavior when placed close to the sound source.
A standardized model with seven steps that determines the communication in, for example, computer systems, regardless of their underlying internal structures and technologies.
Operator
A broadcast network, broadcast station, DBS service, local cable system or cable multiple system operator (MSO).
Optimized Cardioid Triangle, OCT
OCT is a surround sound microphone technique developed by Günther Theile and Helmut Wittek for the front microphone array.
A cardioid microphone is applied for the center channel placed only 8 cm (3.1 in) in front of two directional supercardioids for left and right channels, pointing outwards. The spacing between the left and right microphones is the key to the desired recording angle. Distances between 40 cm (15.7 in) and 90 cm (35.4) are recommended by the designers, resulting in recording angles from 160° to 90°.
One or more pressure (omnidirectional) microphones can be added to the system to compensate for the missing low frequency from the pressure gradient capsules of the cardioids.
Example: The OCT2 variation suggests that the center microphone should be placed 40 cm (15.7 in) in front of the left/right microphone base line, giving longer time differences and spaciousness more like the Decca Tree.
Office de Radiodiffusion Télévision Française (French Radio and Television Office). A microphone setup for stereo recording with two cardioid microphones. Distance between microphones: 17 cm. Angle between microphones: 110°.
1. An audio effect basically applied with guitar sound.
2. In singing: Overdrive is a full-metallic mode. Its character is often direct, loud and shouted, like when you call 'hey' after someone in the street. Overdrive is a mode with a non-breathy sound. When starting out, Overdrive can be found by establishing a 'bite'.
Overdub
A process whereby a track is recorded while listening to already recorded material on the same or a different tape recorder.
Overhead Microphones
Placing microphones above the sound source in order to pick up more ambience with the instrument.
Override
See Ducking.
Oversampling
The use of a sampling frequency that is a number of times higher than is necessary. This makes it easier to make low-pass filters that ensure that no alias frequencies arise in the sound.
Overtone
A harmonic frequency component of a complex tone at a frequency higher than the fundamental. This can involve both harmonic as well as nonharmonic overtones.
Pp
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Microphone Dictionary
Pp
P
Abbreviation for the SI prefix pico (10^-12). See this.
P48
Phantom power see this providing 48-volt DC for the microphones through the XLR connection.
PAC
Perceptual Audio Coding. Bit reduction system from Lucent: 96 kbps.
Packet Transmission
Transmission of standardized data packets over transmission lines or networks of high-speed switching computers.
Pad
Circuit in the input module (for example, in a mixer) with the purpose of preattenuating the signal.
Pan-Pot
Potentiometer in the mixer for "moving" the signal between the left and right channel.
Parabolic Microphone
A microphone element positioned at the focus point of a parabolic screen, which provides amplification of distant sources. Screen diameter determines lower limiting frequency. Small screens are primarily used for (high-frequency) bird recording.
Parallel Port
Digital input or output port with multiple lines, allowing multiple bits of data to be transferred simultaneously.
Partial
One of a group of frequencies, not necessarily harmonically related to the fundamental, which appears in a complex tone. Bells, xylophone blocks, and many other percussion instruments produce harmonically unrelated partials.
Pascal Pa
A unit of pressure corresponding to a force of 1 Newton acting uniformly upon an area of 1 square meter. Hence 1 Pa=1N/square meter.
Pascal's Law
Pressure is transmitted rapidly and uniformly throughout an enclosed fluid at rest.
Passaggi (Italian)
Passages on a pitch scale where the voice tends to change register involuntarily.
Passband
Passband is the description of the frequency range that an electrical filter passes. Outside the passband, frequencies are attenuated or removed.
Patch
Connection of circuits via external connections.
PCM
Pulse-code Modulation. A form of modulation in which the information is described by the number and duration of impulses.
PD
Powered Device. A device that receives power from PoE, Power over Ethernet.
PDM
Pulse Density Modulation. A method for the digitazion of audio.
Peak
The maximum positive or negative dynamic excursion from zero of any time waveform. Sometimes referred to as true peak or waveform peak.
Peak-Hold
Circuit that for a shorter or longer period of time is in a position to maintain a peak value display on an instrument.
PEAQ
Perceptual Evaluation of Audio Quality. A method for determining the objective measurement of perceived audio quality for perceptual coded digital audio signals, as recommended by ITU-R.
Pencil Microphone
A microphone form-factor in which a tube-shaped housing contains a microphone element in one end and a connector in the other.
Perceived Loudness
A loudness descriptor in audio assessment.
How loud the sound is perceived.
Scale: Soft – Loud
[Reference: Report ITU-R BS.2399-0]
Perceptual Coding
A principle for low bit rate coding based on the ear's masking abilities.
Periodic Signal
A signal is periodic if it repeats the same pattern over time. The spectrum of a periodic signal always contains a series of harmonics.
Phantom Powering
A technique for supplying the preamplifier supply voltage to condenser microphones whereby half of the d.c. flows through each signal conductor and returns to the voltage source via the cable shield.
Time lag or lead. The difference in time between two events such as the zero crossing of two waveforms, or the time between a reference and the peak of a waveform. The phase is expressed in degrees as the time between two events divided by the period (also a time), times 360 degrees.
Phase Spectrum
A display of the relative phases versus frequency of a waveform component.
Phase-Shift Keying, PSK
In digital (radio) transmission, a method for modulating a digital signal onto an analog carrier.
Coding strategies for better transmission performance (higher data capacity) encompass higher-order modulation like QPSK (quadrature PSK), DBPSK (differentially binary PSK), DQPSK (differentially quadrature PSK), and further D8PSK and D16FSK.
Phon
The loudness level of a sound. It is numerically equal to the sound pressure level of a 1kHz free progressive wave which is judged by reliable listeners to be as loud as the unknown sound.
Phono Plug/Jack
Plug and jack for one conductor and shielding.
Pico (p)
The SI prefix for a factor of 10^-12, like in pF (picofarad).
Pink Noise
Random noise that contains an equal amount of energy per octave. Compared to white noise the energy is reduced by 3 dB per octave / 10 dB per decade.
PIPU
Punch In Punch Out.
Pitch
The attribute of auditory sensation that orders sounds on a scale extending from low to high. Pitch depends primarily upon the frequency of the sound stimulus but also depends on the sound pressure and waveform of the stimulus.
Plant Mic
A small microphone for hiding in a fixed place on set. Often concealed in a plant or another suitable prop, costume or decoration for close, but invisible, pick-up of dialogue for film or tv.
PLL
Phase-locked Loop. A circuit that ensures a stable frequency in relation to a reference.
Plosive
A transient speech sound generated by a sudden onset or offset of air movement in the vocal tract.
Plosives
A plosive speech sound. The basic plosives in English are t, k, and p, d, g and b.
Referring to the positive or negative direction of a signal. In all stereo and surround sound production it is important that microphones have the same polarity or else the imaging is totally blown.
Polarization Voltage
The (normally high) DC voltage applied to the backplate-diaphragm capacitor of a condenser microphone via a high resistance, thus setting up a fixed charge condition. Changes in the backplate-diaphragm distance due to pressure variations result in a varying output voltage v(t).
Popping
Noise associated with the vocally-induced distortion in a microphone due to consonant sounding, "p", "b", "t" etc.
Post Production
The entire post-processing phase (including editing, sound effects, music, etc.) for video and TV productions.
Pot
Short for potentiometer.
Potentiometer
Adjustable resistance used, for example, in controlling levels.
Power
Source of energy. I.e., electrical power, a product of voltage and current (Joule's law).
Powerful
A dynamics descriptor in audio assessment.
The ability to handle high sound levels, especially when striking the drums and bass. Indicates whether the Punch, Attack and Bass precision are maintained at high volume.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0]
PPM
Peak Program Meter. A meter with a time constant of 5 or 10 ms.
Pre-Aging
A process to stabilize the electrostatic charge of an electret condenser microphone. It also relieves stress in the diaphragm. This process is essential and performed as a part of proper manufacturing. Please note: pre-aging has nothing to do with accelerated aging to reduce the lifetime of a product.
Pre-delay
Pre-delay is a parameter found in reverb processors. It refers to the amount of time between the original dry sound, and the audible onset of early reflections and reverb tail. Carefully adjusting the pre-delay parameter makes a huge difference in the “clarity” of a mix. Also, it defines the perceived room size.
Pre-emphasis
See Emphasis.
Precedence Effect
See Haas Effect.
Prefix
A word, letter or number placed before another. In (audio-) measures, a prefix is used to scale the significant digits by a factor of 10x. Example: 0,00002 Pa can be written as 20 µPa, where the prefix µ (micro) equals 10^-6. (See Numbers in audio).
Prepolarization
A technique of depositing a fixed charge-carrying layer on either the diaphragm or backplate of a condenser microphone, thus eliminating the need for an external polarisation voltage. Such microphones are termed "prepolarized condenser microphones" or "electret microphones".
Presence
The frequency range around 2-5 kHz. Highlighting of this range causes voices and instruments to stand out in the acoustic image.
A transparency descriptor in audio assessment Does it sound as if the sound sources are present and not distant or absent? Scale applied in listening tests: A little – A lot [Reference: Report ITU-R BS.2399-0]
Pressure Microphone
A microphone in which only one side of the diaphragm is exposed to the impinging sound. The diaphragm responds to the pressure variations uniformly and therefore pressure microphones are inherently omnidirectional. Also called "pressure operative microphone".
As sound waves strike a solid surface, the particle velocity is zero at the surface and the pressure is high, thus creating a high-pressure layer near the surface.
Pressure-Gradient Microphone
A microphone in which both sides of the diaphragm are exposed to the incident sound and the microphone is therefore responsive to the pressure differential (gradient) between the two sides of the membrane. Sound incident parallel to the plane of the diaphragm produces no pressure differential, and so pressure-gradient microphones have characteristically figure-of-eight directional characteristics. Also called "velocity microphone", since the output voltage is proportional to the air particle velocity.
"The first passage"; the first register change perceived in a voice.
[Source: National Center of Voice and Speech].
Proximity Effect
An inherent characteristic of pressure gradient microphones, resulting in a boost in the low-frequency response when the microphone is brought closer to a source. The effect becomes significant when the source-to-microphone distance is approximately the same as the wavelength of the impinging sound.
Power Sourced Device. The device that delivers PoE.
PSK
Phase-Shift Keying (see this).
Psychoacoustics
The study of the interaction of the human auditory system and acoustics.
PTP
Precision Time Protocol. Included in the transmission of AoIP.
Punch
A dynamics descriptor.
Specifies whether the strokes on drums and bass are reproduced with clout, almost as if you can feel the blow. The ability to effortlessly handle large volume excursions without compression (compression is heard as level variations that are smaller than one would expect from the perceived original sound).
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
Punch-In
A rerecording of a short sequence in an already recorded program.
Punch-Out
See Punch-in.
PZM - Pressure Zone Microphone
PZM(TM) microphones or boundary layer microphones are taking advantage of special acoustic phenomenons occurring at the surface of a boundary. Product name of Crown.
Qq
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Microphone Dictionary
Qq
Q factor
Measure for the slope of a resonance top.
QoS
Quality of System. A code applied to ensure that packages containing audio data are prioritized in a network, especially if other types of data are transported.
QPSK
Quadrature Phase-Shift Keying (see Phase-Shift Keying).
Quantization
Digitalization of a signal. Conversion of the analog signal to numbers that express the values measured at the time of the samplings.
Quasiperiodic
An imprecise term which is sometimes used to suggest a small deviation from periodicity.
Rr
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Microphone Dictionary
Rr
Radio Wave
Electromagnetic waves in the frequency range of 3 kHz – 300 GHz.
RAM
Random Access Memory (see this).
Random Access Memory (RAM)
Digital storage where data can be arbitrarily stored and retrieved. This is volatile memory, which is an important fact to be aware of: no power, no data.
Reciprocity Calibration
A method for the primary calibration of condenser pressure microphones, 1 inch and ½ inch measurement microphones, in particular. The calibration accuracy is exceptionally high, typical in the range of <0.03 dB. The method takes advantage of the fact that condenser microphones can also act as a sound source, and that the current of the source is proportional to the receiver's sensitivity. Two different methods are described and standardized: The "two-microphone" and the "three-microphone" methods.
Recording Angle
In stereo recording, the angle subtended by the sound source required for a speaker-to-speaker stereo spread. It is the angular width of the performing ensemble (as seen from the microphone array) that causes the full spread.
The bending of a sound wave from its original path, either because it is passing from one medium to another with different velocities or due to changes in the physical properties of the medium, for example, a temperature or wind gradient in the air.
Registers
Perceptually distinct regions of vocal quality as pitch or loudness are changed.
Remote Miking
Placement of a microphone at a distance from the source, thereby picking up a larger proportion of the reflected sound. Also called Ambience Miking.
An environmental descriptor in audio assessment.
Reverberance is the perception of reverberation. The sound that persists after the source has stopped. It may be caused by environmental reflections and scattering or artificially generated. Reverberance is most noticeable when a short impulsive sound stops. However, this will also be perceived with continuous sources, such as an orchestra playing in a concert hall or a cathedral.
Highly reverberant sounds can be experienced in large spaces such as cathedrals, caves, etc. Dry spaces are often small furnished spaces such as living rooms or spaces outdoor without reflecting objects.
Scale applied in listening tests: Dry – Highly reverberant.
Reverberance may be subdivided into “Level of reverberance” and “Duration of reverberance”.
Level of reverberance
The level of the sound that persists after the source has stopped relative to the level of the source.
Reverberance is most noticeable when short impulsive sounds stop. This will also be perceived with continuous sources, such as an orchestra playing in a concert hall or a cathedral.
If a singer is close to the listener in a church the level of reverberance would be low. If the listener is far from the singer in a church, the level of reverberance would be high. Furthermore, in a dry room the level of reverberance would also be low.
Scale applied in listening tests: Low – High. Duration of reverberance
Describes the length of time the sounds take to decay to an imperceptible level, after the source has stopped. Duration of reverberance is most easily judged when a short impulsive sound stops. Duration of reverberance may also be judged with continuous sources, such as an orchestra playing in a concert hall or a cathedral.
A short reverberation duration may be experienced in a small room. A long reverberation decay can be experienced in a cathedral.
Reverberation
Many repetitions of a sound successively closed in time.
The time, in seconds, required for sound pressure at a specific frequency to decay a specified amount after a sound source is stopped. RT60, the time required for a decay of 60 dB, is commonly used.
Radio frequency. Name of frequencies in the range of 30 kHz to 3000 GHz. This is the range for electromagnetic waves applied to radio communication.
RF Power
The power radiated from a transmitter. The power must be adapted to the receiver. Too little power may cause a bad reach. Too much power may cause distortion of the received signal.
RFI
Radio Frequency Interference. Disturbance of the audible frequency range caused by radio frequencies.
Ribbon Microphone
A dynamic microphone in which the diaphraghm is a conductive ribbon in a magnet slit.
Rifle Microphone
Previously, the term used for Shotgun Microphones / Interference Tube microphones. An example is the Electro-Voice Model 643 Rifle Microphone from the late 1950s.
Rigger
A production person on a music stage or film set, who sets up lighting equipment, loudspeakers, scaffolding, etc.
RMS
Root Mean Square (see this).
Roll Off
The attenuation of a high-pass or low-pass filter is called roll off. The term is mostly used for high-frequency attenuation.
Room Mode
The normal mode of vibration of an enclosed space.
The square root of the arithmetic average of a set of squared instantaneous values.
Rough
A signal related descriptor in audio assessment.
A hoarse off-sound unintentionally accompanying the reproduced sound. Bass distortion.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
Routing Switch
A switch for the routing of signals.
RT60
Reverberation time based on the 60 dB attenuation of the sound after the sound source has stopped.
Real-time Transport Protocol. Protocol for the transfer of data for immediate use.
Rubbing
A signal related descriptor in audio assessment.
As the sound of something scraping on a (rough) surface.
Scale applied in listening tests: A little – A lot.
[Reference: Report ITU-R BS.2399-0].
RX
Technical abbreviation for Receiver (wireless systems).
Ss
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Microphone Dictionary
Ss
S/N
See Signal-to-noise Ratio.
Sample Rate
In digital audio: Number of samples per second.
Sample Rate Converter
Converts digital signals with the same reference from one sampling frequency to another.
Sampling
In digital technology: Entry of the signal into discrete values in a table. A single value is called a sample.
Sampling Frequency
The number of samples that are extracted per second. In professional sound equipment: 48 kHz. For CDs and the like: 44.1 kHz.
Scalar
A quantity that scales or adjusts magnitude, a single number.
Schroeder Diffuser
This is a sound-diffusing panel based on a square residual value sequence for scattering sound reflections, usually in one or two dimensions (horizontal/vertical). The diffusers apply in particular to editing rooms, smaller listening rooms, and recording studios. However, also larger rooms benefit from the diffusion of hard reflections, which preserve most of the sound energy (in opposition to the absorption of the sound energy). The physical depths of the panel decide the efficient frequency range.
The principle is invented by the German physicist Manfred Robert Schroeder (1926-2009).
SCSI
Small Computer System Interface. Ultimately a purely computer-related standard, for the control of hard disk drives and the like. It can, however, also carry sound information.
SDC
Small Diaphragm Condenser (microphone). Typically, a mic with a diaphragm diameter less than ½ inch (1.27 cm). Small-diaphragm microphones are generally considered more precise compared to large-diaphragm microphones.
SDDS
Sony Dynamic Digital System. Digital sound system for movies with a total of 8 sound channels: L, CL, C, CR, R, SL, SR and subwoofer. SDDS is bit-reduced with the ATRAC system.
SECAM
Systeme En Couleur Avec Memoire. Television system.
Second-Unit Audio
In larger film and video productions, this refers to the less critical scenes (large crowd scenes, foreign location backgrounds, various inserts, etc.) that are recorded by a smaller, secondary creator.
Secondo Passagio (Italian)
"The second passage", the second register change perceived in a voice.
[Source: National Center of Voice and Speech].
SeDAC
Sennheiser Digital Audio Codec, a codec invented for wireless long-range transmission systems.
Self-noise
See Inherent Noise.
Self-sustained Oscillation
An oscillation that continues indefinitely without an external driving force; since the net energy loss per cycle must be zero, self-oscillation requires an internal energy source.
Sensitivity
Regarding microphones: The output voltage when placed in a SPL of 94 dB. Amplifiers and other audio devices: Expresses the size of a signal that a device requires in order to reach nominal level.
Advertising, commercial, promotional or public service related material or essence. Also termed "interstitial" content. The typical duration is less than approximately two to three minutes.
Shotgun
A directional microphone utilizing an interference tube.
Shrill
A signal related descriptor in audio assessment.
Treble Distortion. Very sharp s-sounds, cymbals etc.
Scale applied in listening tests: A little – A lot
[Reference: Report ITU-R BS.2399-0]
Shuttle Mode
As related to tape transport or DAW track handling: The running of the recording back and forth between two points.
SI Units
International System of Units (Système international d’unités). A coherent system of units of measurement, based on seven base units: Length - meter [m], Time - second [s], Amount of substance - mole [mole], Electric current - ampere [A], Temperature - kelvin [K], Luminous intensity - candela [cd], Mass - kilogram [kg].
Sibilance
Noise associated with vocal sounding of words with characteristically "s", "sch", or "ch" syllables.
A microphone that picks up sound from the side, rather than the end (given the microphone has a cylindrical shape).
Side Lobe
1. Off-axis coloration components often seen (or rather heard) on shotgun mics.
2. When a weighting window is applied to a frequency domain function, side lobes can be seen on either side of the center frequency. The dominance of these depends on the type of window in use.
Side Lobes
An expression related to the directivity pattern of antennas and microphones. The side lobes show the sensitivity versus angle to signals coming from the side. Depending on the design, many sidelobes occur in more complex receivers.
Signal-to-Noise Ratio (S/N or SNR)
The ratio of the maximum signal that a system can record or reproduce to the inherent noise of that system. For digital systems, it is usually defined as the ratio between RMS value of the maximum recordable sine wave and the RMS value of the quantization noise.
In microphones, it has been common to describe the S/N by the ratio given by the sensitivity (= microphones’ output when in sound pressure of 1 Pa, which is the same as 94 dB SPL) to the equivalent level of the microphones’ self-noise. Example: For DPA4060, the equivalent A-weighted self-noise level is 23 dB. Thus the S/N ratio is 94 - 23 dB = 71 dB.
The S/N can no longer be found in DPA microphone specs as it is removed from the standard IEC 60.268-4 Sound System Equipment – part 4: Microphones.
In audio, sine is a tone containing only one frequency.
Singing Registers
In classical singing, it is identified as chest register, head register, falsetto and whistle, respectively.
Sinusoidal Tone
The most simple harmonic tone, consisting of only one frequency.
Slap Back
A discrete reflection from a nearby surface.
Slating
Marking on a recording before a take.
Slope
In audio, the slope describes:
1. The response of filter output outside the passband (i.e., 6 dB per octave, 10 dB per decade, etc.)
2. The decay of room reflections. A decay of 60 dB per second equals a reverberation time of 1 second.
SMPTE
Society of Motion Picture and Television Engineers. International association.
Snake
For PA systems, the bus cable between scene microphones and the mixer in the concert hall.
SNG
Satellite News Gathering. Direct news transmission to main station via satellites.
SNR
Signal-to-Noise Ratio (see this).
SOL
Saturation Output Level. The magnetization level at which a magnetic tape is saturated.
Sonic Character
1.Characteristics of sound as defined from attributes like “cold/warm,” “dark/light,” “cloudy/detailed,” “closed/open,” “skewed/balanced”, etc. When DPA states that a group of microphones represent the same sonic character it means they roughly can be described by an identical set of attributes.
2. Game-related figure (Sonic the Hedgehog).
SOR
Source Oriented Reinforcement (see this)
Sound
Energy that is transmitted by pressure waves in air or other materials and is the objective cause of the sensation of hearing. Commonly called noise if it is unwanted.
Sound Absorption Coefficient
The practical unit between 0 (no absorption) and 1 (full absorption) expressing the absorbing properties of a material.
A sound card is an interface between an audio source – like a microphone – and a computer. Also, it is the interface between the computer's digital audio application and output, like analog line out. The sound card is either built-in or is an independent box containing connectors and level controls for audio and a digital connection utilizing USB, FireWire or Thunderbolt.
A single unit microphone with four cardioid condenser microphone capsules shaped like a tetrahedron. This configuration is also called the A-format. By processing the signals, the B-format is formed equivalent to three figure eight microphones and one omnidirectional microphone, all in a coincident position. A countless number of directional characteristics are obtained by combining the signals in different ways.
An electronic instrument for measuring the RMS level of sound, usually in accordance with an accepted national or international standard.
Sound Pressure
The instantaneous difference between the actual pressure produced by a sound wave and the average barometric pressure at a given point in space. A dynamic variation in atmospheric air pressure. It is a scalar entity describing the level of the sound pressure. At a point in a medium, the difference between the pressure existing at the instant considered and the static pressure. Sound pressure is measured in pascal (Pa).
Sound Pressure Level (SPL)
Sound Pressure Level = 20 log10 (p/p0) [dB]: The sound pressure level of a sound in decibels, is equal to 20 times the logarithm to base 10 of the ratio of the RMS sound pressure to the reference sound pressure 20 μPa.
Sound Propagation
The sound's spread in space.
Sound Wheel
The Sound Wheel has been developed by SenseLab (of FORCE, Denmark) for the purpose of listening tests. It contains descriptors to describe sound.
Wheels like this are generally known in many areas – from wine aroma to concert hall acoustics to psychology.
For film and TV: A large, soundproof area in a studio that allows greater control over the acoustics, lighting, air conditioning and audiences. Often just called a stage.
Soundtrack
In music recording: One or more synchronized tracks on tape or disc that form the full recording when mixed. In film: The audio component of a movie, including the dialogue, musical score, narration and sound effects, that accompany the visual elements. Popularly, it refers to a collection of songs heard during the movie and often sold as an album.
Source-filter Theory
In voice science: A theory that assumes the time-varying glottal airflow to be the primary sound source and the vocal tract to be an acoustic filter of the glottal source.
[Source: National Center of Voice and Speech].
SP
Special Performance. Relates to improved versions of existing video formats.
Spatial Audio
The expression has slightly different meanings depending on the format: The listener is enveloped by sound and can easily and accurately localize it. In VR, spatial audio responds to head position and rotation, it matches the acoustics of the space, and perceptually it is indistinguishable from the real world.
A definition by Anastasia Devana given in 2022: “Spatial audio convinces you that the sounds are coming from the real world around you, and not from your headphones or speakers, and continuously adapts to the changes in the world and your movement through it.”
Speaking Registers
In voice science, it is defined as pulse, modal and falsetto.
Special Effects
A broad, wide-ranging term used by the film industry, meaning to create fantastic visual and audio illusions that cannot be accomplished by normal means, such as travel into space. [Source: Filmsite.org].
Spectral Slope
A measure of how rapidly energy decreases with increasing frequency or, for periodic waveforms, with increasing harmonic number.
[Source: National Center of Voice and Speech].
Spectral Slope Transition
An abrupt voice-quality change that results from an abrupt acoustic change, specifically from sudden loss or gain of high-frequency sound energy at the source.
[Source: National Center of Voice and Speech].
Spectrum
In audio, usually understood as the spectrum of frequencies, a display of relative magnitudes of phases of the component frequencies of a waveform.
Speed of Sound
The table shows the difference in the speed of sound between air and water, different temperatures and between fresh and salt water. Normally we specify the speed of sound (c) in a medium in meters per second [m/s] or feet per second [ft/s]. In the air, the speed of sound is dependent on the temperature: In the air, at 0° C or 32° F, the speed of sound is 331.4 m/s or 1086 ft/s (1193 km/h or 740.5 mph). In the air, at 20° C or 68° F, the speed of sound is 343.54 m/s or 1126 ft/s (1237 km/h or 767.7 mph).
SPFX
See Special Effects.
Spherical Wave
A sound wave in which the surfaces of constant phase are concentric spheres. A small (point) source radiating into an open space produces a free sound field of spherical waves.
Splitbox
A unit that distributes the signal from a microphone to multiple mixers or tape recorders.
Square Wave
Waveform for acoustic or electrical signals that, in terms of frequency, contain a fundamental tone and all the odd-numbered harmonics.
Squelch
In a receiver for analog wireless transmission: A function to mute the audio if the signal is too noisy. Squelch is not necessary for digital transmission as the receiver only opens for valid digital code.
SRP
Stream Reservation Protocol. A term applied to AVB.
See AVB.
Stacked Converters
In digital technology, the principle to apply two converters to cover a dynamic range that is too high for one converter. Normally, the overlap is in a smaller part of the range. This has to be very precise to avoid signal artefacts.
Standard Deviation
If the instantaneous distances from an equilibrium position of a vibrating body are squared and averaged, the result is called the variance of the vibration. The square root of the variance is the standard deviation. It is also equal to the rms (root mean square) value.
Standard Deviation (SD)
In mathematics, the standard deviation (or σ) is a measure of how dispersed the data is in relation to the mean. Low standard deviation means data are clustered around the mean, and high standard deviation indicates data are more spread out. Often applied in acoustical measurements.
Standing Wave
A periodic wave having a fixed distribution in space which is the result of interference of progressive waves of the same frequency and kind. Characterized by the existence of anti-nodes and nodes that are fixed in space.
In music production, stems are sub-mixes of a more extensive mix that will recreate the full mix when played together at an equal level. The purpose is to make it easier to work with the mixing process. An orchestral mix might be stemmed into strings, brass, woodwind and percussion. A rock band might be stemmed into drums, guitars, keys and vocals. By and large, stems are groups of elements that make up the final mix, not the individual elements themselves.
Stereo
A technique intended to created a spatial sound impression by the use of two or more channels.
Speech Transmission Index. Special measurement method and measurement equipment for the objective determination of speech intelligibility in a room. In a good room, the STI value ought to be greater than 0.6 (on a scale of 0 - 1). Practical (reduced) versions that can be implemented in handheld measurement devices are RaSTI (Rapid Speech Transmission Index) and STIPA (Speech Transmission Index, PA systems).
STIPA
See STI.
Stopband
A band of frequencies rejected by a filter.
Streaming Audio
Sound that can be played back immediately in (almost) real time from the Internet.
Sub Harmonic
Sub harmonics are synchronous components in a spectrum that are multiples of 1/2, 1/3, or 1/4 of the frequency of the primary fundamental.
A microphone with a frontal opening angle of 57 degrees, a dead angle at 126 degrees and some sensitivity to the rear.
Supersonic
See Ultrasound.
Surround Sound
A sound production format including multiple channels and loudspeakers to be placed around the listener. The 5.1 format is a standard version of this. Other systems: 6.1, 7.1, TMH 10.2 channels and NHK 22.2 channels.
The optimum listening position in front of the stereo or surround speakers.
Symmetry Attenuation
The attenuation of induced electrical noise signals that is attained in a balanced connection.
Synchronizer
A unit that, by the use of a time code, can deliver control signals for the time-related locking of, for example, tape units.
Synchronous Sound
In film: The sound from a source that is visible in the image's frame.
Tt
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Microphone Dictionary
Tt
Tailored frequency response
A frequency response that is shaped (non-flat) on purpose to enhance the sound for a particular application. In a microphone like DPA 4071, the frequency response is tailored to compensate for the chest-placement and retain speech intelligibility. Also called shaped response or tailored response.
Tails out
A method of winding audio recording tape before storage. Winding the tape backwards leaves the end of the tape (the tail) is on the outside and the beginning is at the center of the reel. Storing tape this way reduces the effect of print through that usually causes audible pre-echoes.
Take
A single, continuously-recorded version of a film scene or music sequence. Typically, multiple takes of the same scene are taken before the producer or the director approves the recording.
Talkback microphone
A microphone used in a talkback system that allows the engineer or producer in the studio control room to communicate with musicians in the studio. Often the talkback function is an integrated part of the mixing console or monitor controller.
Talkies
The common popular term used for films with sound, (beginning in 1923 with engineers Petersen and Poulsen) as opposed to silent films.
Tape Delay
A delay created by using a tape recorder to produce what is called a slapback echo or slapback delay. Originally, some of the signal from the tape recorders’ playback head would be mixed back into the signal going to the record head. Because of the distance between the heads, typical delays were generated in the range of 100 and 200 ms (depending on brand and tape speed). The effect was later refined in dedicated tape machines using endless tape loop and variable speed. The effect is said to be invented - by accident - by Sam Cornelius Phillips, owner of legendary Sun Studios in Memphis, Tennessee.
Tape Speed
The speed at which a magnetic tape passes the magnetic heads in a sound or video tape recorder. Specified in cm/s or inch/sec.
Tape Width
The width of a magnetic tape.
Taping
Outlet from mixer channel, for example aux-send. The expression is used by radio broadcasters.
Target Loudness
A specified value for the anchor element (in some systems dialog level), established to facilitate content exchange from a supplier to an operator.
TB
Talk Back. A system via which the control room can give oral messages to the studio.
TC
See Time Code.
TDIF
Tascam Digital Interface. Factory-initiated interface, 8-channel parallel, unbalanced in a D-sub connector, cable max. 15 m [45 ft].
Telephone Hybrid
Unit that adapts a telephone to a mixer console.
Tessitura (Italian)
Texture; the average pitch level of a song or a part of a song in relation to the overall range of the instrument.
TetraMic
A microphone that is basically similar to the soundfield microphone. (See this).
THD+N
Total Harmonic Distortion plus Noise. An electro acoustic measure of (unwanted) distortion signals from distortion (for instance occurring by the clipping of the signal) and the noise in the given audio channel. Specified in dB below the main signal or in a percentage.
Third-Octave Band
A frequency band whose cut-off frequencies have a ratio of 2 1/3, which is approximately 1.26. The cut-off frequencies of 891 Hz and 1112 Hz define the 1000 Hz third-octave band in common use.
Thunderbolt
Thunderbolt is a digital interface connection standard intended for peripheral devices. The capacity is around 10 Gbps; competing standards: FireWire and USB.
Tie-Line
Connection line for signals (for example, between editing rooms).
TIM
Transient Inter Modulation distortion. Occurs when the feedback circuitry is not acting fast enough when the amplifier is exposed to fast transient signals.
Timbre
The quality of a sound related to its harmonic structure.
Time Code (TC)
Digital code that marks time with information on frames, seconds, minutes, hours, etc. Examples: SMPTE, EBU, MTC.
Time Constants
In transmission and recording, corner frequencies of de-emphasis are often defined by time constants, for example 3180 µs. The frequency is 50 Hz, since the time constant ? = 1/2?f.
Time Difference Stereo
A spaced microphone stereo recording technique which uses left versus right time and phase differences of the acoustic signals to give cues which project to the listener a vivid stereo image. Also known as the A-B stereo recording technique.
Tinnitus
Ringing in the ear or noise sensed in the head typically caused by excessive exposure to high sound levels.
Tinny
A timbre descriptor (treble range) for the assessment of audio equipment.
Resonances or narrowband frequency prominence in the treble or high frequencies.
Scale applied in listening tests: None – Weak – A lot.
[Reference: Report ITU-R BS.2399-0]
Tolerance
The maximum permissible deviation from the specified quantity.
Tonmeister
A German title for an academically-educated sound engineer. The title also applies to engineers' equivalent education in English-speaking countries.
Total Harmonic Distortion (THD)
Distortion in non-linear systems where harmonic components (integer multiples of a fundamental frequency) are produced. THD is normally expressed as a percentage of the fundamental.
A relatively high amplitude, suddenly decaying, peak signal level.
Treble Strength
A timbre descriptor for the assessment of audio equipment.
The relative strength of the treble or high frequencies.
Scale applied in listening tests:
• Weak: Covered, unsharp
• A little under neutral: A soft sound without being dull
• Neutral: In the middle of the scale, where you can clearly distinguish instruments
• A lot: Treble Raised. Sharp, hard sound
[Reference: Report ITU-R BS.2399-0]
True diversity
See Diversity.
True Peak, TP
The maximum absolute level of the signal waveform in the continuous time domain, measured per ITU-R BS.1770. Its units are dB TP meaning decibels relative to nominal 100%, true peak.
Truncation
Cutting off of superfluous bits without weighing their value.
Tube Microphone
1. A (condenser) microphone that uses a built-in electronic tube for impedance conversion and amplification.
2. A special microphone with high directivity, first described by Harry Olsson in 1957. This microphone contains several clustered parallel tubes of different lengths in front of a microphone element. Basically, the function is similar to that of an interference tube microphone.
Turbulence
Irregular movement of air. Creates noise around a microphone.
Twisted Pair
A way to ensure balancing in cables.
Two-Way Microphone
A microphone that includes two capsules to pick-up low and high frequencies, respectively. The principle applies to a few directional microphones searching for unifying the directivity over the complete frequency range.
TX
Technical abbreviation for Transmitter (wireless systems).
Uu
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Microphone Dictionary
Uu
UHF
Ultra High Frequencies. Radio waves.
Ultrasound
Sound at frequencies above the audible range, that is, above about 20 kHz.
Unbalanced
A connection where the chassis/ground is a part of the circuit carrying between electro acoustic devices. Also referred to as single ended.
A name given to a specific single-capsule, dynamic, directional microphone from Shure (Model 55). Designed by Benjamin Bauer in 1939.
Upmix
A technique for the automatic creation of a higher number of audio channels for immersive reproduction of recordings initially recorded in a format with a lower number of channels.; Example: Upmix from two-channel stereo to 5.1 or Dolby Atmos.
USB
Universal Serial Bus. Industry standard that establishes specifications for cables and connectors and protocols for connection, communication and power supply between computers, peripheral devices and other computers.
UTP
Unshielded Twisted Pair.
Vv
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Vv
V.O.
See Voiceover.
Variable-D®
A unique design of a cardioid microphone implementing Variable Distance to the diaphragm's rear. It applies three different paths for LF, MF, and HF. The result is more constant output independent of distance to the source and thus more negligible proximity effect. Wiggins described the principle in 1954, and the design has been implemented and registered by Electro-Voice.
Varispeed
Variable speed, generally in playback systems.
VCA
Voltage-Controlled Amplifier.
VCR
Video Cassette Recorder.
VHF
Very High Frequency. Radio waves.
Virtual Reality (VR)
VR is a computer-generated artificial environment experienced through sensory stimuli, usually presented in VR headsets containing glasses/screens and headphones. The user has various degrees of freedom to move around in the environment controlled by head and body motion tracking.
Virtual Sound Check (VSC)
Recording the live multitrack files from a band either during a performance or during soundcheck and then playing those recorded files back through the console and down their respective channels.
Virtual Studio Technology (VST)
VST is a plug-in format introduced in 1996 by Steinberg for integrating plug-ins with digital audio workstations (DAWs). The VST format has become a kind of a standard that allows third-party developers to create plug-ins that apply to numerous DAWs using the format. There are two main types of VSTs: Effects, sometimes designated as VSTfx, and instruments, designated as VSTi. VST2, VST3 and VST3.5 are updates to the VST plug-in standard introduced in 1999, 2008 and 2011, respectively.
Vocal Folds
A paired system of tissue layers in the larynx that can vibrate to produce sound.
[Source: National Center of Voice and Speech].
Vocal Tract
The airway between the glottis and the mouth is also called the upper respiratory tract.
[Source: National Center of Voice and Speech].
Vocal Tract Resonance
Constructive interference (reinforcement) of waves experiencing multiple reflections in the vocal tract.
[Source: National Center of Voice and Speech].
Voice Range Profile
A visual display of vocal intensity range versus fundamental frequency.
[Source: National Center of Voice and Speech].
Voiceover
1. Recorded dialogue, usually narration, that comes from an unseen, off-screen voice, character or narrator. It can be heard by the audience but not by the film characters themselves.
2. Also means Ducking. See this.
Vokes
Slang for Vocals.
Volt (V)
Unit for voltage measurements.
Volumetric audio
A method for manipulating spatial sound to provide information on the sound sources’ position.
Vowel
1. A speech sound produced by vibrating vocal cords. When passing the vocal tract, the mouth and the nasal cavity, various vowels can be created depending on the position of the palate, jaw and tongue. The cavities act like acoustical filters.
2. A letter representing a vowel sound, such as a, e, i, o, u.
Vpp
Measure of the magnitude of an electrical voltage from peak to peak.
VR
Virtual Reality, see this.
VSC
Virtual Sound Check (see this).
VST
Virtual Studio Technology (see this).
VSTfx
VST Effects (see VST).
VSTi
VST Instruments, a VST format to generate audio using virtual synthesizers or samplers. Some of these are designed to emulate the look and sound of famous hardware synthesizers. A regular VST plug-in generally is used to create effects and is sometimes designated as VSTfx.
VTR
Video Tape Recorder.
VU
Volume Unit. A meter for audio recording; time constant: 300 ms.
Ww
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Ww
WAN
Wide Area Network.
WASAPI
Windows Audio Session Application Programming Interface (see this).
Watt (W)
The unit of electrical or acoustical power.
WAV
Waveform Audio File Format. "WAVE" or "WAV" is the standard Microsoft audio file format having the extension ".wav." Usually, the structure applies to storing uncompressed audio bitstreams on Windows computers.
Wave Impedance (acoustic)
In a sound propagating medium, the ratio of acoustic pressure to the speed of air particles is driven by this pressure.
Waveform
A plot of any variable (e.g., pressure, flow, velocity, or displacement) changing as time progresses along the horizontal axis. The basic display of the DAW.
Wavefront
The initial disturbance in a propagating wave.
Wavelength
The distance measured perpendicular to the wavefront in the direction of propagation between two successive points in the wave separated by one period. Equals the ratio of the speed of sound in the medium of the fundamental frequency.
WaveRT
(Wave Real-Time). A Windows port driver applied for real-time rendering and capturing of audio streams.
Weber, Wb
Measurement unit for magnetic flux.
Weighting
Adjustment of the time or frequency response of a measuring device to achieve a desired prescribed filtering. Time weighting, for instance, in metering devices: 10 ms, 300 ms, 400 ms, etc. Frequency weighting, for instance in sound level metering devices: A-weighting, C-weighting, Z-weighting, etc.
Weighting Network
An electronic filter which gives different weighting to signals at different frequencies, commonly to approximate the frequency response of the human ear under defined conditions. The A-weighting network is most commonly used (as in dB(A)).
Wente microphone
This condenser microphone was invented in 1914 and patented in 1916 by E.C. Wente. It is often referred to as a capacitor or an electrostatic microphone. At the time, Wente worked for Bell Labs and his task was to improve the audio quality for telephones, but his work also enhanced the microphone.
Whisper
Sound created by turbulent glottal airflow in the absence of vocal fold vibration.
Whistle Register
The highest of all registers (pitch). It occurs in females, extending the pitch range beyond F6 (the sixth formant).
[Source: National Center of Voice and Speech].
White Noise
Broadband noise having constant energy per unit of frequency.
Whoop-Whoops
When editing sound effects, this refers to the extra noises added to a sound, to increase interest or excitement. Sound effects for film or drama often consist of multiple layers of sound. [Source: Filmsite.org].
Wide Cardioid Microphone
A microphone that has a directional pattern between an omnidirectional and a cardioid.
A spatial descriptor in audio assessment.
The perceived extent of a sound source, ensemble or scene from side to side. A narrow (or a wide) source may be perceived in any direction seen from the listener, i.e., in front of the listener, or to their side, above them or anywhere around them.
A single talker in a dry environment might be perceived as narrow. An organ in a church may be perceived as wide.
Scale applied in listening tests: Narrow – Wide
[Reference: Report ITU-R BS.2399-0]
Windows Audio Session Application Programming Interface, WASAPI
WASAPI is a driver that enables DAWs and other audio applications to manage the flow of audio data between the application and a device for Windows 7 and higher.
Wobble
In singing: A slow vibrato resulting from lack of excitement, poor muscle tone or fatigue.
Working Level
The signal level at which a circuit is nominally modulated. Also called the "0-level".
Wow
In audio recorders or reproducers: Variation in speed, audible if >± 0.08% WRMS (Weighted RMS).
In singing: Modulation in the 1-2 Hz range.
WRMS
Weighted RMS value. The abbreviation is also used for the RMS value of the power.
Xx
Microphone Dictionary
Xx
XLR
Professional cable connector for audio. Pin 1: shield; pin 2: +; pin 3: -.
XR
X stands for “whatever” and R is the abbreviation for “reality”. Most known examples: VR: virtual reality; AR: augmented reality.
XY
A recording technique with two angled cardioid microphones arranged so the capsules are as close together as possible (coincident).
The zoom microphone design is developed to be used with cameras to follow the zoom of the lens. The design consists of three first-order cardioid capsules combined in different ways to provide directivity going from omni to second-order cardioid characteristics.
Zwicker loudness
A method for expressing the loudness of complex sounds. The method is developed by the German acoustics scientist Eberhard Zwicker (1924-1990), based on a model that simulates the nonlinear sensitivity of the human ear. This loudness measure utilizes the unit of phon see this. The method is primarily related to quantifying perceived noise in the workplace.
0 - 9
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1st Order Pattern
Standard microphone patterns like cardioid, supercardioid or figure-of-eight are known as first-order patterns. Their polar equations are composed of various ratios of unity and cos θ taken to the first power. The patterns range from omnidirectional (basically order 0), when the cosine term is zero, to bidirectional, when the constant term is zero. The various combinations of these two basic patterns yield the family of cardioid patterns.
Omni ρ = 1 + 0 cos θ
Subcardioid ρ = 0.7 + 0.3 cos θ
Cardioid ρ = 0.5 + 0.5 cos θ
Supercardioid ρ = 0.37 + 0.63 cos θ
Hypercardioid ρ = 0.25 + 0.75 cos θ
Figure-of-eight ρ = 0 + cos θ
3:1 Rule
Phase peaks and dips from the same sound source occur when panned to the same position at the same level, which will be the case using more than one microphone. A rule-of-thumb for minimizing phasing issues is to have around 10 dB level difference between the microphone contributions. The 3:1 distance rule addresses this need. Another workaround is to pan microphones in the mix, which will, by the nature of panning, also create level differences.
Three or six Degrees of Freedom. Listeners’ (or viewers’) position in a sound field. It applies to virtual reality and immersive sound recording. 3DoF: Yaw/pitch/roll. 6DOF: Yaw/pitch/roll/forward-back/up-down/left-right.
4FSK
Four Level Frequency Shift Keying. In digital wireless transmission: The carrier is modulated by four different frequencies, each representing two bits, i.e. 00, 01, 10,11. See also FSK.
5.1 Surround Sound
An audio format involving five channels of full bandwidth audio: center, left, right, left surround and right surround. A special low-frequency effects channel (LFE or ".1") covers a frequency range from 20 Hz to 120 Hz. The basic setup for music production is defined in ITU 775.
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