Friday, August 3, 2012

SNR 101 - EQ, The Very Basics

I was on the phone recently, helping out a friend of a friend get something going at the last minute. This person confessed to being a complete neophyte on a console, especially with respect to EQ.  So I took a look at what I had already posted on the subject and realized it was some pretty intense material. This post is all about what to do when you're stepping up to your first console and facing an EQ section that's not really like anything you've seen before.

Most small consoles have knobs in the EQ section that are roughly equivalent to the bass and treble knobs that you're used to seeing on a stereo.  These will almost always be shelf type which means that instead of having a bell shaped curve that's centered on a given frequency, they start at the frequency they're labeled at and carry out right to the edge of the sound spectrum.

Let's start with that low knob. It's probably working on frequencies from 80Hz or 120 Hz on down. On most channels you want to take that and turn it down a little or a lot. This gets rid of a lot of meaningless extra bass that will clog up the system. If the channel you're working on starts to sound too thin then put a little back in.

On the high side you can be looking at anywhere from 2.5kHz (kilohertz or thousands of cycles) right on up out of hearing range. Often it's labeled as to what the frequency is but sometimes you'll have to look it up in the manual. Think of this as being the "Ts" and "Ss" on a vocal channel, the pick sounds on an acoustic guitar. Call it "air" or "sparkle" or whatever you want. Be extremely careful about turning it up though, you can get into real trouble. Raising the highs can make feedback more likely and will definitely make ear fatigue more likely.  Keep in mind that most people will like a sound with boosted highs better, but it's a temporary thing, you keep needing more and more until people are bleeding from the ears.  You can either leave these right alone or pick and choose which channels really need the highs. Backing down the highs on some of the instrument channels, especially electric guitar and synth can make some room for vocal clarity.

Now the mids. Very small consoles will be lacking this knob entirely. Some will have just a single knob that works on a single frequency, and some will have a second knob that lets you change that center frequency.  Whatever the case, the mid EQ will be a notch type which means it's working on a specific frequency and as you move up or down from that center frequency it's affecting things less and less. It's helpful to think of it as being at one house on a street but affecting a small neighborhood.

If it's fixed it's Murphy's law that it will be at a frequency that won't help you. It will be at 2.5kHz when you have issues at 800Hz and vice versa. If you've got a sweep knob you're in luck. It can be intimidating. You're saying, "I don't know what frequency I need to adjust, I just know it sounds bad!"  But take heart, you've got a pair of ears on the sides of your head and that's all you need to solve this puzzle.

If you've got a channel and it just doesn't sound right you can just hunt around for the right frequency. If it's boomy you can guess that you should start low or if it's nasally you should start higher. Turn the gain knob for the mid all the way down and run the sweep knob back and forth until you notice the stuff you don't like disappearing. Then turn the gain back up until it sounds right. If that's too tricky, turn the gain knob all the way up and sweep back and forth until it sounds the worst, then cut.

It's that simple. Once you've done it a bit you'll start to have a bit of arcane knowledge at your finger tips. You'll know that a muddy male vocal needs to be cut around 200, and a shrill female vocal needs cut between 800 and 1.5k. You'll build up a small library in your head that will give you a starting point but always use your ears.

That's it Brethren of the Knob and Fader. If you're just starting out on EQ you've got the primer. If you're already mixing at Jedi level, you've got a link to an easy lesson on EQ that you can point people to if you're teaching. Good luck!

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