The basis of any drum sound will begin with the overhead microphone/s. There are many different schools of thought as to what an overheads purpose is and depending on the style of music you’re working on, they can be targeted towards different tasks. For most cases, the overhead setup should be the representation of the overall sound of the drum kit you were honing in the previous chapter, so the size of the kit you’re trying to represent will dictate the stereo field you opt to employ. Smaller, more basic kit setups will capture perfectly with one overhead as a mono signal, but obviously larger scale kits with more constituent parts will require a wider pickup. Now you can argue that you can widen the ‘pickup’ of the microphone by moving further away (imagine a torch light’s spread getting larger as you get further away from the destination), however if we are still considering a bedroom scale recording setup it’s likely that a standard 5-piece kit will require two overheads to capture a more balanced representation of the whole kit without surpassing the height of the room.
This brings us nicely to the main reason why recording drums can be so difficult. The more microphones you introduce the more you introduce phase. We can use phase to our advantage in some cases, but for the sake of explanation we’ll consider it for now as a negative effect. If we consider the bass drum as the centre of the drum kit, we need to be sure that the distance from the bass drum to the left overhead is the same as the right overhead. This means that the sound of the bass drum will arrive at the same time to both mics, and therefore be in phase. Now if we consider the general position of the snare drum within a drum kit, it’s slightly to the left of the bass drum, but by doing that the snare is now closer to the left than it is the right overhead which will mean that the sound coming from the snare will arrive out of phase in relation to the other.
We’re in a bit of a predicament… we only have 2 drums and two mics up and already we’re having phase problems. Some techniques such as the Weathervane technique (linked here) employ a method of overhead positioning that allows for both the bass drum and the snare drum to be in phase, however we’ve found this to be pretty time consuming. Some engineers will say that since phase tends to be most audible in the low end, they will measure equidistant from the snare and accept that the kick might be out of phase since the bass drum low end will come more from the spot mic than the overheads. However, if you think within a mix context, bass drums and snare drums tend not to be panned meaning they reside down the middle of the stereo field. So if we take that concept and work backwards, we can consider the kick and snare to be in the same position by drawing an imaginary line between the snare and kick and then positioning the overheads equidistant left and right of that imaginary line. This means that the phase relationship between left and right will be much closer for both snare and the kick since they now both reside down the middle of the image. You can then adjust the angles, positioning and heights of the mics to taste so long as you maintain the kick snare centre line and measure the mics to be equidistant to that centre line.
Some engineers will say that since phase tends to be most audible in the low end, they will measure equidistant from the snare and accept that the kick might be out of phase since the bass drum low end will come more from the spot mic than the overheads.
You might notice that we haven’t mentioned what microphones to use. Well, this in intentional. Partly because no situation is ever the same and everyone has different microphones to their disposal. But more in line with the aim of this blog we have the sound right at the source, so we only need a microphone to capture that accurately. In this case, any microphone will work so long as it’s relatively flat response full range and has the capability of withstanding the SPL a drum kit can output. Condensers are the popular choice here for that reason, but do we need tube microphones or vintage ribbons? Not necessarily, since these mics all colour the signal and if we have the source sounding right we shouldn’t need to colour it. We can at this point use particular mic characters to our advantage if we weren’t able to fully solve a problem at the source. For instance opposites always work well (bright sparkly microphones for dark and dry signals and dark and a mellow microphone for a bright and harsh source), but this only comes into affect if we couldn’t fix the problem primarily at the source.