Overhead mics are hugely important in creating a great drum sound, and a lot of the time they are massively under valued. Unfortunately it’s common to just focus on all the close mics and having them really high in the mix, whereas you could be getting half the sound of the kit from just these two mics.
They certainly play a very large part in the tone and sustain of the snare drum, as well as providing most of the cymbal and toms sound. The low end tends to be their downside, and this is partly due to the kind of mic chosen but mostly because the kick drum isn’t very close and directs most of its sound horizontally, away from the overheads. With just the overheads, a snare mic and a kick mic, you should be able to get a complete drum sound working well.
This is mostly down to personal preference and what you think works well, but here are a few pointers to help you make that decision.
- dynamic vs condenser
Dynamic mics are unlikely to have a useful effect here as most rely on being very close to the source to get the proximity effect and their natural compression going. Condensers tend to be more popular for overheads and are also generally more sensitive to high frequency.
By using cardioid mics, you can get a reduced amount of room reverb and a good stereo image. The frequency response of omni-directional mics generally goes lower than cardioid mics, but they will need to be closer to the kit because they pick up more reverb and spill. In limited space, two figure-8 mics at 90° to each other will give an excellent stereo image, but will not have the low-end of omni’s and will pick up more room reverb than cardioids.
- large vs small diaphragm
Small diaphragms have a naturally higher frequency response than large diaphragms (see here for more techie details) which can give you a really shimmery cymbal sound, but some engineers prefer large diaphragm condensers for exactly this reason. There are plenty of other differences in transient response, sensitivity etc. and ultimately it comes down to personal preference in each application. For more info, read up on getting the best from condenser mics
By placing two mics over the kit, you instantly get a clear stereo image of the whole instrument. This can be very useful when it comes to panning close mics, as it allows you to have a very natural sounding reference to compare to. Bearing this in mind, when you position the overheads take care to balance the kick and snare sound centrally between them. If the kick or snare are off center, then you can get strange effects when the close mics are mixed in and panned centrally; the initial impact can be perfectly central but have the sustain draw out to one side.
It’s difficult to get both the kick and snare drum physically central between the two and effectively cover the whole drum kit, so to compensate try angling the left mic slightly away from the snare drum without moving it further away. That way, it remains close to the high tom, high-hat and cymbals but the snare drum sits more central in the stereo image from the overheads. Of course moving the mic further away, or towards the back of the kit will have a similar effect but it will be prone to picking up more room noise and ambiance / reverb.
Next time your in the studio with a drum kit, just listen to the overheads on their own and work to get them sounding as good as possible for the whole drum kit. Don’t just think of them as cymbal mics!
So here’s a challenge for you:
Record a complete drum kit using just one kick mic, one snare mic and two overheads. Can you do it?
[image via Olivier Engel]