What’s all the fuss with drum room mics? Character, depth, density, and bloom. That’s what. Putting some distance between the source you’re recording (a snare drum for example) and the mics allows the sound of that source to bang around all the surfaces in the room for a while before being captured. During that journey the sound is shaped; the surfaces and materials of your room absorb and reflect various frequencies, putting their sonic stamp on the soundwaves. The dimensions of the room can exaggerate and resonate some pitches and reduce others. All that bouncing (a room has a bare minimum of 6 surfaces, right?) diffuses the sound in time — spreading that snare drum thwack into a longer tone that has had a chance to develop (bloom).
Sound samples (good speakers or headphones recommended)
All 3 sound samples are from the forthcoming Stuntdriver album, recorded at Wondersmith Studio. These are excerpts from in-progress sessions and feature little to no eq or processing. Linecker Da Silva is the player.
Let's start with a nice tight dry drum sound with just a bit of pleasing natural ambience in the close mics:
Next, I’ve added a stereo pair of Avantone CV-12 large diaphragm tube condenser mics about 10’ away, 2’ off the ground, making an equilateral triangle with the kick drum. I measure the distance from each mic’s capsule to the same point on the kick drum to guarantee that the kick drum sounds in phase. Notice the drums sound bigger and wider and the snare drum has more tone and depth:
For example 3 I’ve added a single distant room mic about 35’ away and facing backwards at the other end of the room. There’s a natural delay from the distance and a definite sonic fingerprint from the slap off the stone wall. Same player, kit, room, and take. New drum sound from adding that 1 mic:
So it’s reverb, right? Yes, essentially. Rooms are what reverbs (whether they be digital, spring, plate, etc.) are imitating. But whereas a digital reverb would take your close mics and put them through an algorithm simulating a type of room — your room mics are entirely separate analog inputs with their own unique coloration. You get to choose the mics, preamps, compressors or other processing, and play with placement just as you would with any input. There’s an infinite world of possibilities there and the end result is going to have character and a unique identity.
Can you record drums without room mics? Sure. Perhaps you don’t have enough mics, inputs or time. You can still get a variety of tones from close mics (and for certain genres that’s more appropriate) using various types of processing. But even in an ordinary small room, if you can get away with it — put up a couple. Try pointing them at the walls or floor. Use those bizarre mics you got at a yard sale that smell funny. Take chances. You might end up with a sound you can blend with your close mics that brings character, depth, density, and bloom. And it won’t be a preset on anyone’s hardware reverb or plug-in.
Oh and here’s one iconic drum sound from the Pixies that wouldn’t be possible without a kick-ass room sound.