A drum kit can be difficult to record or amplify optimally because of its size and complexity. It can include a wide range of instruments like kick (bass), snare, overheads, tom-toms, hi-hats as well as supplemental elements such as chimes, wood block, cow bell, etc.
Each individual element of the drum kit has its own unique sound to capture. So, when miking the kit, your first consideration is whether to capture the sound “as is” - meaning the whole drum kit as a person hears it acoustically or capture the sound of each element separately.
Due to the complex nature of the kit, the close proximity of the elements often creates a lot of cross talk between each instrument, which can be beneficial or a huge challenge, depending on your end goal.
If you wish to capture the natural sound and dynamics of the kit, you can choose to use few microphones, strategically placed to capture the entire drum kit. This can be over the drums or slightly behind or even in front of the kit. This approach will usually result in a sound that the drummer can recognize.
If you consider each drum, cymbal, and other element of the kit as separate instruments, and close-mic each of these accordingly, you can potentially end up using many microphones. This will result in a much different sound than the other approach, with the final sound mostly in the hands of the recording engineer and producer.
Either way, the environment, whether on the live stage or in the recording studio, will have a major impact on the sound, and thus the best approach to use.
Kick drum (aka bass drum)
Kick drums come in many sizes and sounds. All have a batter head on the beater side and most also have a resonator head on the opposite side. The resonator head helps the bass drum resonate at a specific tone and is often tuned very specifically to give a preferred sonic character of the drum. The resonator head often has a hole that makes it easier and faster to place a microphone inside. Yet, placing a microphone just in front of this hole can often capture a good combination of the sound of the batter head and the resonator head. Placing the microphone all the way inside creates a very distinct sound with a lot of attack - the sound of the beater hitting the batter head. Placement outside the hole creates a more “boomy” sound. Often a combination is desired. Angling the microphone when placed outside the hole will alter the sound and sometimes give you just the attack or the low end you are looking for as well.
Angling the mic will also reduce potential wind issues (a lot of air is moved by the kick drum). Distance will adjust the overall bass frequency response, taking advantage of the proximity effect. It all depends on the sound you wish to produce as well as the instrument and drummer.
More on miking a kick drum
Snare drum
The snare drum is named after the “snares” at the bottom of this type of drum. Thin metal strings tightly strung across the head. These snares resonate when hitting the batter/top head and are therefore a distinct part of the characteristic sound of a snare drum.
Capturing the bottom snares separately can often be beneficial for later mixing so a designated microphone is often used for this.
Years ago, microphones were not capable of capturing the extreme sound pressure levels and the required high frequencies generated from the snare drum. It was always either or. A workaround was to place one microphone, capable of handling high frequencies below the drum, where the sound pressure wasn’t that extreme. On top of the snare, another microphone, typically a dynamic, handled the extreme sound pressure level. This combination gave us best of both worlds, but also introduced phase issues between the types of microphones placed at different distances to the batter head of the drum.
Today these problems are solved with high-end condenser microphones that can handle extreme SPLs and capture high frequencies.
More on miking the snare drum
Overheads
You can use overheads to compliment the close miking and focus on capturing the cymbal sound. Depending on the number of cymbals and the size/width of the drum kit, you might need more than one microphone. A stereo pair is often used, and several stereo techniques are useful.
AB stereo is popular with omni and directional microphones. When placing more than one microphone as an overhead, it is a good idea to secure that the distance from the snare is the same to both. This will secure that the level, time and phase of the snare drum is the same in both overhead mics.
In some cases, an underhead miking technique is preferred. This technique allows the cymbals to be treaded more individually and is also sometimes preferred for practical and visual reasons.
Hi-hat
If the style requires the hi-hat as a distinct part in the drum mix, and not just naturally reproduced in the overhead pair, a designated microphone slightly above the cymbals can be used. The center of the hi-hat radiates higher frequencies and goes lower as you place the microphone closer to the edge. For more separation, positioning the hi-hat mic facing away from the snare is good trick but since the microphone is pointing at a reflective surface, you will hear a lot of spill from the rest of the drum kit.
More on miking hi-hat
Tom-toms (aka rack toms)
Tom-toms can be miked the same way as the snare, except that the tom-toms have no snares underneath so capturing the resonator head has a different purpose. Pointing the microphone closer to the rim creates a higher pitch attack and pointing it more towards the center of the drum will generate a low end, more boomy sound.
Tom-toms have different roles depending on the style played so some considerations and genre aesthetics are appropriate. In some genres, it is not common to use tom-tom mics at all. In these cases, accurately placed overheads are used to capture a balanced sound. But for pop and rock, the tom-toms require a closer miking technique to achieve a very isolated signal to process individually.
It is recommended to experiment with the position and different angles to find the desired sound and minimize the bleed from the cymbals, which are often very close to the mics on the tom-toms
More on miking tom-toms