Drum Heads: Big Drums In Small Rooms
We all want huge, thick drum tones that drive the mix and give it
backbone. To this end, we employ better microphones, top-of-the-line
cables, quality preamps, and high-end converters. Each of these things
will certainly make improvements in the sound, but I would argue that
the most important element in the recording chain—besides the source
sound, of course—is the room itself.
TL Space models a host of different ambient environments including recording studios, concert halls, reverb chambers, stairwells, and garages.
A great set of drums in a great room sounds amazing. The same drum set in a bad room can sound like the drummer is playing his cases—a situation I refer to as the “bucket effect.” If the snare drum sounds like someone is hitting a bucket instead of a drum, there’s a problem with the room. For example, the bucket effect often occurs when the drums are on heavy carpeting, as the sound can be choked and hollow.
Because the room has such a drastic effect on the drum tone, home studios can be at a disadvantage when compared to the glorious live rooms of big studios. This doesn’t mean you can’t get great drum sounds in a home or project studio, it just means you have to do a little more work and be a little more creative. Let’s examine a few ways to fatten up drum sounds in a small room.
IDENTIFYING DUFF DRUM TONE
First, let’s talk about what’s causing your drums to sound, well, small. Although this is oversimplifying things, the main issue is that small rooms don’t let sound waves develop and breathe, and early reflections (sound bouncing off close walls and ceilings) often cause phase issues that can thin out the drum tones. To minimize the effects of early reflections in tiny home studios, recordists often cover everything with heavy absorptive materials, which makes the drums sound even more lifeless. Basically, you’re fixing a problem with a problem.
There is nothing wrong with early reflections. In fact, they can make the drums sound fatter (as long as the reflections aren’t too fast). It’s the very close boundaries (more on this later) that can cause phase shifting. The other issue is that small rooms have very little natural reverb. While too much reverb (or decay time) can make drums sound washy and inarticulate, the lack of reverb can make drums sound small and choked.
DOING BATTLE WITH PHYSICS
Knowing that acoustics will always win if we don’t follow the rules, here are some tips for getting big drum sounds in small rooms.
Don’t set up drums too close to walls. Early reflections within approximately 7ms can cause phase shifting and comb filtering. When possible, keep the drums a minimum of four feet away from the walls, as this should produce a total combined time of at least 8ms of reflection time to the wall and back from the wall. (For math freaks, reflections typically travel at 1.13 feet per millisecond, so keeping the drums four feet away from a reflective surface buys you approximately 4ms from source sound to the surface, and 4ms from surface back to the source sound and microphones.)
Don’t smother your room. Reverb is our friend. A small amount of absorption can keep reflections from getting crazy, but using too much will kill decay time and make the drums sound lifeless. Absorption should be distributed strategically around the room while leaving live areas on the walls and ceiling. You don’t have to be an acoustics expert—just use your ears. Move your absorptive materials around, and listen critically to determine which combination of live and dead areas in your studio sounds the best.
Go with wood. Of all the building materials that can be used in a studio, wood is king. Not only does it make a room livelier, but most woods reflect the audible frequency range pretty evenly so that a room’s natural EQ stays flatter. In addition, wood’s early reflections are very flattering— a big plus for recording drums. So make a wood floor part of your studio’s sonic equation—even if it means throwing down a couple of pieces of plywood. (A small, thin rug can be used to keep the drums from sliding around.)
Diffuse. Diffusion evenly distributes some of the random reflections in a room, making the enviroment sound open and spacious. Home studios can embrace this effect by hanging diffuser panels on the walls, or by simply putting other objects in the room (such as instruments, music stands, or even people—although people will absorb, as well).
Control reflections off low ceilings. As many home studios are in homes, ceilings tend to be lower than what you’d see in a commercial recording facility. Early reflections from low ceilings can wreak havoc with drum tones, so use some absorption directly over the drums to minimize the adverse effects. Here’s another tip: Avoid omni overhead mics in this situation, as they’ll “hear” more early reflections than mics with tighter polar patterns (such as cardioid).
Compress the room. Set up a couple of room mics some distance from the drums, and compress them heavily to punch up the room tone. Of course, a small space still won’t produce as much “air” as a large room, but this technique should still improve punch—especially if you experiment with the positioning of the room mics.
As the saying goes, “If you’re going to steal, steal from the best.” A great way to get big drums is to use someone else’s sound. Here are two sonic thievery options for augmenting your home-studio drum tracks.
Reverb Plug-Ins. Impulse or convolution reverbs are a great way to add quality reverb timbres to drums tracking in small spaces. These types of reverbs (Audio Ease Altiverb, Trillium Lane Labs TL Space, Digidesign ReVibe, etc.) are actual models of real spaces. This means that if your room doesn’t sound so amazing, you can stick the drums in a tweaked studio or famous concert hall by simply running some of the channels through the reverb. Admittedly, you won’t get quite the same results as cutting in a great room, but this is a fantastic way of cheating the system. I find this option to be especially effective on overheads and room mics, as these mics capture the entire drum sound. An effective technique is running the overheads through a convolution reverb to produce openness and space, and then using a short plate reverb for any close mics (toms, etc.).
Samples. Having a library of quality drum samples has become standard for many mix engineers, and many major releases employ drum replacement or augmentation. Why fight fashion? Now, you can have some of the best drum sounds ever recorded at your fingertips. I’m not a fan of replacing drum sounds completely, as this can sound rather artificial and unnatural no matter how good the samples are. I do, however, like to augment the original drum sounds with samples to fatten them up, and “steal” some of the room tone from a bigger studio. I used to augment drums only when a player had a bad-sounding set or didn’t hit the drums well, but, lately, I’ve found that if I slip in a little bit of the samples even when I have a good sound to begin with, it makes an improvement. It also makes mixing go faster, because the drum samples are dialed in already. But let me point out that, although drum replacement and augmentation can do wonders to a mix, the technique doesn’t work everywhere. For big, solid drum grooves, it’s a miracle cure. If the mix needs something more natural or dynamic, however, samples can sound campy and fake. Like any good application of audio engineering, the key is to know what to do, or what not to do.
A small absorption canopy on a low ceiling can be effective at keeping early reflections from causing phase issues.