This post focuses on the basics of equalization.
Equalization is something that most people are probably pretty familiar with on a basic level, having some EQ capacity in their car stereos and portable players. Essentially, EQ is cutting or boosting of frequencies or frequency ranges.
There are fundamentally two kinds of equalization: graphic and parametric. Graphic EQ usually has set frequency points with sliders to boost or cut at those points. Parametric usually has a set of moveable frequency ‘centers’ with a width control, combined with a cut and boost knob.
EQ Best Practices
One of the golden rules when it comes to EQ is that it is sonically better to cut than boost. Cutting is usually used to fix problems, whereas boosting is generally used to change the character of the sound. This comes from the fact that EQ (with the exception of a few specialized digital mastering EQs such as the Waves Linear Phase EQ, available in the Platinum Bundle) creates phase shifts. If sonic integrity is desired, it’s best to use EQ as little as possible (instead relying on mic placement and mic & preamp choice to determine the sound before any other gear).
Parametric EQs tend to provide accuracy with the ability to narrow the width (called the ‘Q’) of the EQ down to a fine point. This means that you can use parametric EQs to cut out hum, hiss, or other narrow frequency noise.
Most people EQ first before compression and other effects, but there’s no hard rule about this.
A highpass filter is basically an EQ that allows high frequencies above a certain set frequency to pass and low frequencies below that frequency get rolled off.
Similarly, a lowpass filter allows low frequencies below a certain setting to pass and high frequencies get rolled off.
Some EQs, such as the SSL G series have ‘resonance’, which is basically a little hump before or after cuts and boosts to give the adjustment more character.
Try not to cut a lot or boost of instruments in exactly the same frequencies as those frequencies will become empty or crowded. The goal is a nice complimentary balance.
The Frequency Ranges
0-30hz – This range is the subsonic range. Few people can hear much below 25hz and very few speakers reproduce frequencies much below 35hz. As a result, many engineers aggressively cut in this range to reduce the amount of headroom and sonic energy that these sounds take up. This is the sort of frequency range that will seriously make your shoelaces move.
30-65hz – This range is the gut-impact low end range. Sounds that have frequencies in this range compose the rumble and gut-impact of the sound. Many engineers use high pass EQs in this range or even higher to prevent competition for bass real-estate. Bass guitars, kick drums, and synths are some of the instruments that produce a lot of sound in this range.
65-120hz – This is the body of the low end where bass frequencies have their impact. Many subs have crossovers in this area, either at 80hz, 100hz, or 120hz. Again, many engineers like to cut this range aggressively for non-bass-oriented instruments such as guitars and vocals. 80-120hz is probably where you’ll find yourself needing to sculpt out bits of bass instruments to get them to work together well.
120hz-250hz – This range is the low mids. Low mids are frequencies that give body and girth to sounds. If things sound too thin, try adding a little bit in this range. If things sound too thick, try cutting a little bit. 250hz is one of those problem frequencies that you hear a lot of folks talk about as a lot of instruments have lots of energy at this frequency. As a result, this is the most sensitive area and it’s one of the things that experienced engineers focus on controlling.
250hz-1000hz – This range is the mids, where a lot of the ‘tone’ of sounds reside. Things with too much mids sound ‘honky’ whereas things with not enough can sound ‘fizzy’ or soulless. Disco records are notoriously scooped in the mids. I try not to suck out too much of the mids in my mixes because a lot of ‘hi-fi’ speakers cut this range to produce an illusion of clarity.
1khz-3.5khz – This range is the sibilant range where you’ll find the attack and spit of instruments such as the pick noise of guitars and the smacky bit of drum impacts. Most vocals have their esses, tees, and other hissy phonemes in this range. Our ears are most sensitive in the 2-3.5khz range (so that we can hear those critical speech phonemes well), so if things sound harsh, check this range first.
3.5-8khz – These are the high mids. Many amps call this range ‘presence’. Electric guitars, for instance, don’t extend much beyond 8khz, so boosting 6-8khz increases their sparkle and cut. Elements that are strong in this range sound closer to the ear.
8-12khz – This range is the ‘air’ range. Cutting these frequencies can make sounds sound artificial or spaceless. Boosting these frequencies tends to increase the ambience and livens up the sound. It’s popular to boost artificially generated sounds like synths in this range to give them a bit more of an organic character. 8-10khz is where you’ll find the breathiness of a snare.
12-20khz – This is the, uh, super air or sparkle range. Our ears aren’t very good at discerning these frequencies, but they contribute to the present and airy qualities of their lower harmonics such as 6 and 10khz. A bit of trivia… CRT monitors tend to produce a 17khz hum.
When I’m looking to get rid of a gross frequency, Ill usually solo the sound, set a parametric EQ to an 8db boost or so, and sweep across the spectrum until I hear that frequency really stick out. Then I’ll cut it appropriately.
My favorite EQs
For sweetness and highs, I adore the API 550 series. For character I’m a big fan of the SSL G series for mids and the Neve 1064 for low-end. For sculpting the whole sound spectrum, the API 560 is awesome. For mastering digital material the Massenburg stuff is top notch, although I have used Avalon gear too. My go-to mastering EQ for analog or analog/digital material is the Waves Linear Phase EQ I mentioned earlier as it doesn’t color the sound at all.
For those on more of a budget (that’s the majority of us!) it’s really hard to go wrong with the Waves Renaissance EQ. It’s accurate, easy to use, and doesn’t sound too digital. I have yet to use a general purpose digital EQ that I like better (although I’m keen to try the new Waves API and SSL packs).