Getting your drum mix right
While this article is centered on mixing “in the box” using a workstation, these methods can easily be ported over for those working on a traditional or digital console.
First things first
Before diving into a new song, I highly recommend first familiarizing yourself with both a rough mix of the song and the style you are working in. Drum sounds vary drastically within pop music and you can save a lot of time by knowing both the quality of what has been recorded and what your sonic goal is.
Like most engineers, I start a mix by laying out my (virtual) console, setting up sends and returns, and labeling all necessary faders to optimize creativity. For drums, I almost always set up a separate stereo bus and assign all drum tracks to this “stem”. While every engineer has a slightly different approach for drum stems, I set up two stereo aux returns set to source from the drum buss and assigned to output to the main stereo mix.
On the first stereo aux return I insert a compressor, and with it I highly compress (“spank”) the drum mix. On the second return I place no effect and I use this for the basis of my drum sound. By increasing the amount of compressed drums in ratio to the “clean” return, I can greatly thicken up and intensify the overall drum mix. Also, these two stereo returns in effect become the drum masters. As the mix progresses, any overall adjustment in drum level can be done by simply trimming these two stereo returns in unison.
Kick and snare
Once the initial setup is complete, it is on to the kick and snare. When defining a kick and snare, I prefer to have multiple recorded mics to mix together. In the ideal world, the kick will have been recorded as separate inside-and-outside-the-drum tracks, and the snare will be comprised of at least separate top and bottom mic tracks. I will often add kick and snare samples to further strengthen the drum sounds. (Please see the Drum Column in the August 2005 issue for in-depth information on sample replacement.)
My standard procedure for the mixing of the kick and snare is to create separate aux busses for both. I simply assign all of the kick tracks to one buss and all of the snares to another. If recorded properly, they may not need eq on the drums’ multiple tracks and I can get away with a single equalizer placed on the aux buss. Although major eq surgery is often required to fix poorly recorded drums, a tightly defined boost at the drum’s fundamental and a gentle boost in the high frequencies (for attack and harmonics) will usually suffice. If the drum does not sound good, separate equalizers may be needed on the individual tracks. For readers new to eq: be sure to use a parametric, and sweep the frequency control to find the exact frequencies to be adjusted.
When mixing the multiple mics together, always check phase and polarity relationships. Simply solo the kick or snare buss, insert a plug-in capable of reversing polarity onto each mic’s track, and toggle combinations of polarity until you determine the punchiest sound. I cannot stress enough that polarity is the key to phat drum sounds! You may even want to zoom in on the waveform of the separate kick mics and check for phase alignment. Moving the outside-the-drum kick track to match the inside mic can seriously beef up the low end. (Michael Schulze got a bit obsessive—but not too obsessive—about this topic in our July 2005 Drum Column, “Problems of Multiple Drum Miking”, which is available in this website’s Resource database.)
In addition to eq, I usually add a slight amount of compression to the kick and snare busses. Drum compression helps even out the drummer’s performance, adds attack to the drum, and can help create a more modern drum tone. While compression may not always be necessary, it is invaluable for keeping a kick and snare punchy and present in a crowded mix. Be sure to test all available compressors to find the one that best suits your taste. I usually prefer drum compressors that are fast in attack and release, and I usually only limit by a few dB.
Overheads and room mics
Once the snare and kick are defined, I examine the overheads to determine the general ambience and dimension around the drum kit. If room mics have been recorded, I will also include them in this process. Depending on the style of music, cymbal use, and the distance of the room mics, I use drastically different amounts of the overheads and room in each project I mix. Sometimes I find myself with the overheads turned off and a sound rich in room. Other times a totally dry approach is required, and the room gets the mute. While it’s nice to have many recorded mics to experiment with, you do not have to use them all in the final mix!
Compression and equalization are also options on room and overhead tracks. While many engineers love to compress the room heavily to make it bigger and more intense, this usually does not suit my personal taste. On the other hand, eq is almost always found on my overhead and room tracks. I love to boost the sizzle of cymbals and gouge strange resonances in the room tracks. I also frequently filter low end in the room. Without filtering, a thick room can muddy up the presence of the kick buss.
As with the kick and snare, be sure to try all combinations of polarity with the overheads and room tracks. Examine the low end of the kick, the punch of the snare, and check for any hollowness in the room. In some cases, when the room appears to phase out the close mics no matter what you do, try moving the room tracks earlier in time. While this may make the room sound smaller, it might also save the close mics and allow you to have a roomy sound that still offers punch and clarity.
Hi-hat, toms, reverb
The hi-hat mic is another part of the mix that may or may not be needed. Depending on the volume of the hat in the overheads and room mix, I frequently find that an extra mic is unnecessary. Experimentation and stylistic analysis are key to hi-hat choices.
Tom toms are an essential element in pop music. Like most engineers, I do not particularly like tom leakage, and choose to gate the toms in the mix. While the traditional method for gating involves finely tuned outboard noise gates, in the workstation environment it is much easier to analyze the tom tracks and manually mute and fade any unneeded song sections. As with other drums, adjust eq and polarity to taste. Although the practice is rare, some engineers apply compression to toms.
Once all of the separate drums have coalesced into a single mix, I usually choose one or more reverbs to add judiciously to the isolated drums. Although reverb choice and amount varies once the other instruments enter the mix, I usually devote a rather natural room to the kick, snare, and toms. There are no norms with effect usage, however, as every musical style requires a completely different approach.
A side note in the discussion of mixing within a workstation involves plug-in latency (usually defined as time lag between input and output). While some platforms compensate for this latency, it is important to know that every plug-in imparts a small delay. While this may not necessarily affect single-track instruments such as a vocal or guitar, it can drastically alter the overall sound of a multi-miked drum kit.
A perfect example of this involves the two aux returns I use as master faders for my drum mix. As mentioned earlier, I buss the complete drum mix to separate compressed and non-compressed aux returns. In the workstation I use, Pro Tools TDM Mix, the drum compressor (a Bomb Factory Fairchild 660) delays the signal by three samples. While this is not a long period of time, when mixed with the non-compressed (and therefore non-delayed) aux return, the overall sound turns into hollow, comb-filtered garbage.
Luckily there is a simple solution to this problem. To compensate for the compressor’s delay, I insert a plug-in on the unaffected aux return with the corresponding amount of latency. Since a Waves Renaissance EQ also has a three-sample delay, I use this plug and set the eq to bypass. The Waves plug-in delays the signal even in bypass and my drum mix still sounds good. Check to see if plug-in latency is an issue on your workstation and investigate if there is a simple way to calculate delay, and for more information check my DAW Details column in this issue.
Mixing involves a variety of techniques guided by personal taste and musical style. While there are standard methods that most engineers employ, every mixer inevitably develops his or her own methods through experimentation and education.
Eric Ferguson, LA-based engineer and musician, was touring the world with Lee Ritenour and Friends when this article went to press– now he’s back home in Los Angeles. Learn more about his work at www.bluecupmusic.com and write to Eric via firstname.lastname@example.org.