by Chris Munson

Overview
It is safe to say that the equalizer is used more frequently than any other signal processing device. EQ’s are both amplitude and spectrum processors. This is because they can affect both the dynamic range and sonic quality of an instrument. The most common types of EQ’s include graphic, fixed frequency, and parametric. I will be discussing the use of parametric equalization only.

Before getting into the nuts and bolts of EQ’ing, it is important to understand what it is you are altering. Look on any EQ and you will find some numeric representation of frequency. Next to the number will be either the abbreviation Hz (hertz) or kHz (kilohertz). Frequency is engineer lingo for pitch and is expressed over a range of 20 Hz to 20 kHz (the human range of hearing).

Anything that generates pitch / sound creates sound waves. These waves go through cycles of upward (peak) and downward (trough) movement several times a second. The number of cycles completed per second is expressed in hertz. So twenty cycles per second equals 20 Hz and 20,000 cycles per second equals 20 kHz. Think of the 20 Hz to 20 kHz range as going from the lowest audible pitch to the highest.

How EQ’s Work

On a parametric EQ you will find controls for gain, frequency, and Q (bandwidth). Additionally you will usually find filters and shelves which are not available on every parametric EQ but are still pretty common. The flexibility of these controls varies. At the low end of spectrum you may be able to alter only three frequencies simultaneously. At the high end of the spectrum you may be able to alter five frequencies simultaneously and have separate controls for filtering and shelving.

The gain allows you to boost or cut a specific center frequency.

Changes in gain must be at least 3 db (decibels) to be audible. The Q allows you to boost or cut frequencies surrounding the center frequency. The Q can be very wide and drastic or very tight and minimal. Filters are either low-cut / high-pass or high-cut / low-pass and eliminate frequencies above or below a set point. Shelves are a sort of combination of the previous two and are used to boost or cut frequencies above or below a set point.

Before you begin using EQ it is important to keep a few things in perspective. First, no amount of EQ will turn poorly recorded drums into amazingly recorded drums. Be weary of the engineer who says they will ‘fix it in the mix’ later. Second, be aware of the cumulative nature of EQ. If you boost the same frequencies on several tracks you will likely cause problems in your overall mix. Third (and I think most important), try a reductive approach to EQ’ing. For example, if a snare sounds too muddy it may be your instinct to boost some highs. However, by doing this you are not correcting the problem. You will be better suited to eliminate the problematic sounds, thereby clarifying your track.

An important thing I learned early on as an engineer was to associate adjectives with frequency ranges. What follows are some of the descriptive words I associate with enhancing or correcting drum tracks and the frequency ranges they fall into:

Bass (20-200 Hz) – Boom, punch, power, thick, thin, hollow
Low mids (200-600 Hz) – Fat, warmth, depth, cloudy, muddy
Mids (600 Hz – 2 kHz) – Snap, crisp, nasal, ring, boxy,
Upper mids (2 – 6 kHz) – Sizzle, bright, metallic, muffled, crack
Highs (6 – 20 kHz) – Air, edge, bright, height, tinny

When EQ’ing your drums, I suggested you first listen closely and objectively to your sound. Try to define what you dislike and want to enhance. Find the general frequency range, boost the gain, and sweep the EQ until you begin to find the sweet spot. Then cut the problematic spot or adjust the gain and Q to bring out the desired element.

The following audio examples contain A/B example of flat and EQ’d drum tracks (kick, snare, overheads, and combined). I have included screen shots of the EQ profiles as well.

Kick

Overheads

Snare

KICK A_B.mp3 | OVERHEAD A_B.mp3 | SNARE A_B.mp3 | Overall A_B.mp3 | PDF

Chris Munson is currently the Director of Recording Arts at Eastern Kentucky University where he teaches courses in music technology and applied drum set. He has been a professional musician and audio engineer for over 15 years. Over that time he has recorded or performed with: Don Aliquo, David Amram, Darol Anger, Danny Barnes, David Carradine, Vassar Clements, Jeff Coffin, Joe Craven, Jerry Douglas, Tom Harrell, Jorma Kaukonen, Jon McEuen, Tim O’Brien, Greg Osby, Anders Osborne, Merl Saunders, Jamey Simons, and Trout Fishing in America. Albums he has appeared on have earned numerous awards including two Grammy nominations.