Mixing Drums | Beefing Up the Beat

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FIG. 1: The tom tracks (in the middle of this screenshot) were erased wherever the toms were not sounding, eliminating bleed from other kit pieces.

Much has already been written about mixing drums, so rather than restating the basics, I'll share with you tips and advice that you're less likely to have read about elsewhere. The focus will be on mixing real trap drums, but much of what I'll cover applies equally to sampled drums.

There are many strategies to mixing (and tracking) drums. I'll mostly talk about my own approach, in which the close mics in a multi-miked drum kit are used as the foundation of the overall sound, and overhead and room mics are added to achieve the proper balance of cymbals, inter-mic bleed and room ambience. Most of the discussion will assume the kick, snare and individual toms were each recorded to a separate track prior to mixdown. I'll include DAW techniques everyone can use and reveal my favorite plug-ins for processing the kit. I use these plug-ins on my Mac, but all of them also run on Windows and are available in a variety of formats.

Ground Control to Major Toms

While a healthy amount of drum bleed between the close mics on various kit pieces is key to preventing the drums from sounding like a canned drum machine, too much bleed can lead to unfocused and thin-sounding kick and snare drums. The first places to reduce excessive bleed are the tom tracks. In most arrangements, the toms are the least often played parts of the kit, so it makes no sense to have their mics always “open.”

Some engineers use expanders or noise gates to reduce bleed of other kit pieces into tom mics, but I never use them for that purpose. Expanders don't provide enough attenuation for my tastes, and gates can chatter or cut off the attack and natural sustain of toms. The best solution is to simply erase the tom tracks along your DAW's timeline wherever they're not playing (see Fig. 1). The occurrence of tom hits in a track can be readily ascertained by slightly zooming in on the track's waveform(s). Delete the track from its start up to the beginning of the first tom fill. Then resume deleting after the tom fill ends — after the toms have stopped ringing — all the way up to the start of the next fill. For the most transparent results, resume deleting immediately before a quarter-note beat; a kick or snare hit there will mask the sound of the tom track “shutting off.” Continue deleting to the end of the track wherever a tom fill isn't happening. Do this for every tom track.

Make sure that all tracks for individual kit pieces are phase-aligned with each other. For example, if you've miked the kick drum both inside and outside the shell with separate mics (each recorded to a separate track), make sure that the peaks of their waveforms line up perfectly along the timeline. If they don't, slide the outside mic's track forward (earlier) in time so that the two tracks align. (You may also need to flip the outside mic's phase 180 degrees.) For all kit pieces recorded with multiple mics to separate tracks (kick drum miked both inside and outside the shell, and toms and snare miked from the top and bottom), use the track for the side of the drum that was closest to the stick (or beater) hit as your phase reference and slide its companion track earlier in time to align the phase of the two tracks. Doing so will increase the bottom-end punch for each phase-aligned kit piece, sometimes dramatically.

Don't forget to also align the phase of the overhead and room mics to the close mics on the kit. My mixing style often entails EQ'ing out some of the kick drum bleed on these tracks during mixdown so that their sonic focus is on the snare and toms (and, for the overheads, on the cymbals). For this reason, I align the overhead and room tracks to peaks on the snare track, not to those on the kick track.

At this point, your trap drums should already be sounding more powerful and focused. Let's take the whole kit to the next level by adding some processing.

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FIG. 2: The SPL Transient Designer plug-in offers independent controls for boosting or attenuating the levels of the attack and sustain portions of a sound.

Trap Attack

Many engineers use separate compressors on kick, snare and toms to increase their attack. For each track, the basic approach is to adjust the compressor's attack time so that compression doesn't begin until just after the stick (or beater) hit has passed. (Because every type of compressor has different attack characteristics, you'll need to set the attack time by ear.) When the compressor kicks in immediately after the stick hit, the level of the ringing drum shell is lowered. This has the effect of emphasizing the attack portion of the drum hits. A compression ratio of around 5:1 usually gets the job done. A fast release time of about 20 ms will usually return levels to unity gain before the next hit occurs, thereby preserving its attack.

Another approach is to send each drum to a stereo subgroup — with each drum panned in the stereo field as desired — and apply compression to the subgroup instead of to individual tracks. The compressed subgroup is typically then blended in with the original, uncompressed tracks. Combining the density of a compressed subgroup with the unfettered dynamics of the unprocessed original tracks better preserves the fundamental drum sounds.

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FIG. 3: The Waves API 2500 Compressor plug-in models the compression curve and character of the critically acclaimed API 2500 hardware bus compressor.

All that said, applying compression on close-miked drum tracks seems like a backward approach to me, and I never do it. I prefer boosting the attack (isn't that the goal?) rather than squashing the sustain to put a point on kick, snare and toms. The Sonnox (sonnoxplugins.com) Transient Modulator, SPL (spl-usa.com) Transient Designer and Waves (waves.com) TransX plug-ins all provide controls that boost (or attenuate) the attack portion of a sound and are awesome processors for drums (see Web Clips 1a and 1b). Transient Modulator and TransX offer far greater control over the attack envelope as compared to Transient Designer, allowing you to adjust — among other things — how much (in duration) of the transient will be processed. Transient Designer, however, offers something the other two plug-ins don't: an additional control that adjusts the sustain portion of the sound (see Fig. 2). You can use it to lower the level of a snare drum's decay, for example, to reduce hi-hat bleed. Or radically increase the sustain to give the snare drum a trashy, more ambient sound.

Although I avoid using compressors on close mics for traps, I love using them on tracks for room (and sometimes overhead) mics. Used in this way, certain compressor plug-ins can make a tame drum kit sound downright raucous. On room mics, set the attack time to roughly 30 microseconds to clamp down quickly on the drums. The release time should be set to about 100 ms to have the compressor recover quickly after each strike. With a high ratio of around 10:1 and between 10 and 20 dB of gain reduction applied during peaks, the compressor will dramatically boost the room ambience and make the drums pump. Blending this processed track in with those for the close-miked traps is a recipe for explosive drum sounds. The Waves API 2500 stereo compressor (see Fig. 3 and Web Clip 2) is my favorite compressor plug-in for room mics — it sounds as good as any analog compressor I've heard for this application. The PSP Audioware (pspaudioware.com) VintageWarmer2 and Xenon limiter, Softube (softube.se) FET Compressor and Waves SSL G-Master Buss Compressor are other compressor and limiter plug-ins that sound awesome on room mics.

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FIG. 4: In addition to conventional M/S equalization facilities, the Brainworx bx_digital plug-in provides a one-knob solution for centering bass frequencies in the stereo field.

Many other articles have detailed how to apply EQ to drums, so I'll just mention a few special considerations. There are applications where precise digital filters excel, but EQ'ing traps, in particular, is not one of them. You want analog character and color. The Waves Studio Classics bundle provides dynamite models of vintage analog hardware equalizers that are the best I've heard yet for beefing up drums. In particular, the Waves SSL G Equalizer has an extended low end that's great for creating punchy kick tracks. For a raspy snare drum with rocking midrange definition, the Waves API 550A 3-band parametric can't be beat. And the Waves VEQ4 (which models the vintage Neve 1081) excels at shaping round, colorful toms.

As a mix engineer, I sometimes receive projects in which the drum kit was recorded using only two mics set up as a stereo spaced pair. In this case, the kick drum usually doesn't have enough low-end punch. Boosting the low end with a static equalizer (one that is continuously active) can make the entire kit sound rumbly or boomy. The solution is to process the stereo drum track with a dynamic equalizer that briefly triggers a low-frequency boost only when the kick drum hits. The Brainworx (brainworx-music.de) bx_boom plug-in is an idiot-proof tool for this purpose. This plug-in requires adjustment of just two controls: One sets the threshold at which the effect will kick in, and the other sets the frequency (32, 48 or 64 Hz) for the plug-in's bandpass filter to boost. In seconds, you can make the kick drum thump without adding rumble to any other elements of the stereo drum track.

Sometimes no amount of low-frequency EQ boost will give the floor tom the bottom-end thunder you desire because the low-bass frequencies just weren't captured while tracking. (You can't boost what's not there to begin with!) The solution is to shift the pitch of the tom downward. The best-sounding pitch shifter to my ears is the Celemony (celemony.com) Melodyne plug-in. Insert Melodyne on the floor tom track, click on the plug-in's Transfer button and play the track from start to finish. Choose the Percussive algorithm from Melodyne's Algorithm drop-down menu. Then select all the tom hits in the editing area of Melodyne's GUI and drag them together three or more semitones lower in pitch. The result will be a behemoth sound no equalizer can produce. It usually sounds best to use just the pitch-shifted track instead of blending the processed and unprocessed sounds together. Blending them together can cause wobbly sounding beat frequencies to occur.

If EQ and pitch shifting don't perk up dull, lifeless drums, try adding some harmonics and analog-modeled saturation. The SPL TwinTube plug-in offers controls for adding harmonics in one of four selectable frequency bands. This is a fantastic way to bring out the beater slap on a kick track or the stick hit on snare and toms. Another TwinTube control lets you independently dial in the amount of tube-type saturation you desire, adding girth and richness to thin, sterile traps.

On the other hand, you may prefer to make your drum tracks sound like they were recorded to tape. The DUY (duystore.com) DaD Tape plug-in does a wonderful job emulating the tape-compression effects of analog multitracks from different eras. Simply select the type of tape machine you want the plug-in to emulate, and adjust your input and output levels.

The panning of each of your drum tracks has a major impact on how focused and powerful your drums will sound. Don't automatically assume that overheads should be hard-panned left and right. Pay special attention to how panning toms and overhead mics in combination affect the imaging of each trap drum. For example, a slight pan adjustment on a rack-tom track or moving one side of a stereo overhead track slightly toward center can improve the pinpoint imaging of the rack tom considerably.

Mid/side (M/S) techniques — commonly used in mastering — are also a boon to improving the imaging and clarity of room mics while mixing. M/S processing separates a stereo track into discrete mid and side channels. The mid channel comprises everything that is common to both channels of the stereo track (mono signal). The side channel contains all elements of the stereo track that are dissimilar in the left and right channels, such as room ambience.

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FIG. 5: WaveMachine Labs'' Drumagog can be used to replace or beef up lifeless drum sounds with multisampled drums.

If you hard-pan room mics left and right to make the ambience sound wider, their tracks may have too much low-frequency content (from the kick and toms) spread across the stereo field. This can compromise the clarity and imaging of the entire kit. Rather than just thin out the room mics by cutting low frequencies, the Brainworx bx_digital plug-in (see Fig. 4) offers a more elegant solution. Among its many features, this stereo and mid/side equalizer includes separate mid and side output-level controls and an innovative Mono Maker control. The Mono Maker control essentially converts stereo bass content to mono by simultaneously applying shelving cut to bass frequencies in the side channel and boosting the same frequencies in the mid channel. Set the Mono Maker control to between 60 and 100 Hz to center the low-bass content of drums in the room mics. (The higher frequencies that largely give directional cues will remain in the drums' panned positions.) You can also cut the mid channel's output level and boost the side channel's output level in the plug-in. That will reduce the level of the kick and snare, raise the volume of cymbals and room ambience, and widen the stereo image (see Web Clip 3). Brainworx's bx_control and bx_hybrid plug-ins also each include a Mono Maker and stereo-width controls.

Of course, adding reverb to snare and tom tracks is also key to giving your drums extra dimension, especially if the kit was recorded in a small room. Much has been written about this in other articles, so I won't rehash it here. For general guidelines on adding reverb to trap drums, see the Online Bonus Material at emusician.com/bonus_material.

When time is of the essence, the Waves Maserati DRM Drum Slammer plug-in provides macro-parameter controls for lickety-split, idiot-proof operation. DRM sounds especially flattering on kick and snare, adding low-end thump to the former and transient-enhancing definition to both.

If you're still not happy with any of your drum sounds after applying all of the tools and techniques mentioned above, you can use drum-replacement software such as WaveMachine Labs (drumagog.com) Drumagog to replace real drum sounds with samples. Drumagog can be quickly set up to trigger a multisampled snare, for example, every time your real snare is struck (see Fig. 5). The triggered snare sounds can either replace your tired acoustic snare drum completely or be layered with it to create a beefier tone.

The Pro and Platinum versions of Drumagog have yet another trick up their sleeve. Say you're mixing a song in the key of E and your kick drum lacks bottom-end thump and sustain. Drumagog's Synth section can make your kick track briefly trigger a sine wave along with a multisampled kick. Tune the sine wave to 41 Hz (a low-E tone). Every time the kick hits, the 41Hz sine wave will voice — at the volume and for the duration you specify — the root of the song's key and add deep sustain to the layered kick drum sound. With Drumagog, you're never stuck with the drum sounds you've tracked. The sky is the limit.

Michael Cooper recently had one of his songs cut on Dave Russell's new project, produced by Jerry Cupit for Cupit Records. Hear Cooper's drum sounds atwww.myspace.com/michaelcooperrecording.