Re-Thinking EQ – A Powerful Method

Tom has a worked out a method for approaching EQ that is remarkably effective. It is a general purpose process for dealing with specific individual tracks that very effectively addresses some of the issues that always made me crazy. I took it home, tried it immediately, and said to myself, “Well, hot damn.”

What Happens When We Cut Frequencies?

You all probably know the basics of this. It’s comparatively hard to hear EQ cuts. Further, when we cut, the level of the signals usually doesn’t change much at all. So, it has become an audio verity that we cut when we wish to conceal badnesses.

What Happens When We Boost Frequencies?

Meanwhile, when we boost, we exaggerate parts of the spectrum, audibly emphasizing them. The level of the signal DOES go up as well, almost as much as the amount of boost we use. So, the audio verity here is that we boost when we wish to ENHANCE a sound.

Fixing problems first –

Tom’s approach is to fix the problems first, by cutting. How he does this is a model of evolved audio process. Listen up! This is worth the cost of your subscription for the next five years.

First, we find the offending frequencies. Then we find their bandwidth (some call it Q). Then we figure out how much to cut them. Cool, eh? What could be simpler?

To do this, you need a parametric equalizer, hopefully with a lot of bands. Working in Pro Tools, I use the Waves Q-series plug-ins, guessing how many bands I’m gonna need in each case.

Finding Problem Frequencies

So how do you find problem frequencies in a given track? Well, by using your ears, of course! But you can give them a little (actually a lot of) help. Start by dropping the overall level of the track by 10 dB. Set the Q at 8, which is like a 10th of an octave, pretty narrow. Crank one band of EQ all the way up to max, typically +18 dB.

Now, sweep the frequency (I start with high frequencies, ca. 10 kHz. and work my way down), gently and slowly, listening for the truly ugly resonances, the ones that make your teeth itch or your sinuses act up. If the track distorts on some frequency band, drop the level some more until the distortion is gone (if it never goes away, then you’ve got distortion on the track at that frequency – obviously you’d like to hide it!). What I’ve found is that the problem frequencies are pretty obvious. They are unpleasant resonances of the instrument (or the instrument/microphone interaction).

So let’s assume you find a real nasty at 2641 Hz. It just jumps out at you, says “UUUUGGHLEEE!” at the limits of your monitors, puts little hairline cracks in your vintage Oakleys (you should never mix wearing Oakleys, by the way). See Figure 1.

	Figure 1. A Waves Q4 plug-in on a Pro Tools session (stereo, in this case). Note that the plug-in “rounded” my 2641 Hz. to 2650 – annoying but not significant.

Determining An Appropriate Q to Correct Them

Now you narrow the Q all the way until you have just this poor tormented single 2641 Hz. frequency whistling and spitting at you (Figure 2).

	Figure 2. The same setup as Figure 1, but now we’ve narrowed the Q to 100, which is as narrow as this plug-in will go.

Very slowly, start widening the Q. Listen for the point where you BEGIN to hear parts of the sound that are OK. Now the Q is slightly wider than the offensive frequency band (Figure 3).

	Figure 3. Same as above, but now we've "widened" the Q to 3.2, by which point we‘ve noticed that we are hearing parts of the track that are outside of the annoying band of resonance.

Narrow it back slightly so the nice stuff JUST BARELY goes away. Now you’ve found both the problem frequency and its bandwidth (Figure 4).

	Figure 4. Finally, we’ve narrowed the band again so we’ve got just the annoying resonance, nothing more.

Time for a break.