Tech Tip:Miking Drums (Part 1): How Many, and Where?
by Douglas B. Henderson
Part 1: Available Equipment/Too Many Mics
If there are a lot of ways to skin a cat, there are ten times as many ways to mic up a drum kit. What works best for your recording will ultimately depend on the equipment available to you, the type of music, and the drummer's playing style.
The essential factors to consider before deciding on a specific miking technique are:
- How many mics do you have and how many inputs are available?
- What kind of music are you recording?
1. Simple economics: How much equipment do you have or can you borrow?
This may be the most important factor, and it figures into all levels of recording from big-budget releases to 4-track productions in a home studio. In any session, I take out the best, most expensive mics in the studio and put them on the drums. (It's unfortunate but true: Money talks when it comes to mics and mic pres. Don't let anyone tell you otherwise.) Then I scrounge around for stuff for the other instruments. Drum kits, because of their dynamic range and central focus, are the hardest instruments to capture on tape.
However, plenty of great tracks have been recorded using just two microphones. Take a look at photos from the Abbey Road studios during the Beatles' sessions: one mic in the middle of the kit, and one about four feet in front of the kick near the floor (see Fig. 1). Okay, so they were using Neumann U47's, which would cost around $16,000 a pair today. But the acoustic principle is the same. You could mic up a kit like this with Shure 57's and get a nice recording.
Close miking means lots of stands, lots of cables, lots of inputs, lots of time and phase headaches, and lots of $$$. If you can figure out a way to use just a few mics, and you select high-quality ones, you may very well wind up with a better, more manageable sound overall. Since you'll be using less tracks, you'll take less time in mix getting a drum sound up, and you'll have more tracks available for your girlfriend's stupendous flute solo, without which your relationship will inevitably fail.
2. More is not necessarily better.
The stripped-down scenario suggested above has other payoffs, too. The more mics you have in close proximity, the more trouble you will have with conflicting phase relationships between them. Sound takes time to travel from place to place - approximately 1 millisecond per foot of distance - and it radiates in all directions, especially at bass frequencies. Say your drummer hits the kick drum and you have eight mics up, each being at a different distance form the kick. The initial pressure wave radiates out from the drum, catching first the kick mic; then, in a disordered sequence, it arrives at all the other mics you' ve set up with a slight and differing delay for each. The net result of this is a warping of the low frequency response (this is the most noticeably affected area) which can either reinforce or horribly sap the punch and boom of the kick drum.
Of course, the same sequence of events occurs for all the drums. The snare may start to sound tubby or papery, not from your excellent snare mic placement but from some interaction with a mic on a ride cymbal, tom or kick. High frequencies are also affected and the cymbals can become grainy or harsh as a result of phase discrepancies. These issues can be worked out by careful placement (which requires a lot of trial and error) and by use of outboard gates, though this will remove much of the natural character - not that that's necessarily bad, it just depends what you're going for.