Yup. And we are not talking about the U2 guitarist this time, even though he might be related. Somewhat. It’s about that very distinctive tonal character, that most instruments have. Then you go and take it away, in the name of smoothness and an overall good sounding mix, dear n00bie. What’s this edge and why you shouldn’t take it away?
The edge you used to have
Well, the edge is this disturbing, obtrusive quality that you hear from most instruments live. The one that has the potential to make you cringe. It’s a combination of (midrange) resonance and the build-up of overtones (it’s not high treble). Think of potential lead instruments like a trumpet, sax or fiddle; electric or acoustic archtop guitar; banjo or dobro; snare drums or certain lead vocals etc. All those aggressive sounding things. When you hear someone play these by themselves, or solo their tracks in the mix, the “problem” will be apparent. So you go and EQ the living, throbbing crap out of it. Turn the whole mix on, and voilá: the problem’s gone, so does the character. Sometimes the instruments are almost completely disappear as well.
Smooth is the new boring
There are two reasons why you shouldn’t take this upper midrange edge away. The first one is pretty obvious: you reduce the overall level too much by turning it down, so you need to compensate, and turn it back up. When you do that, you end up having to fight both low and high end masking. Don’t forget the zen of EQ: taking away the middle is the same as turning up what’s around the middle. In the end you’ll find yourself combating the EQ of several different elements; typically things you never had problems with previously.
Disturbance is your friend
The second reason you should keep the edge intact might not be that technically obvious. It’s pretty much the artistic reason out of the two. An interesting mix is the sum of ever so slightly imperfect elements. Yes, you read that right. Perfection is the result of imperfection. How does that happen? Remember, we are magicians. If you make everything perfectly smooth, the resulting sound will be an uninteresting sugary sweet boredom. Listen to it once or twice, and it might sound impressive. Listen to it three times and you’ll find yourself snoozing after the first verse. The disturbing edge provides character, it’s the dirt in the otherwise impeccable machine. If you take it away, you’ve taken the uncontrollable, random reality out of the equation. Leave it in, and you’ll preserve the psychological effect that makes the listener hit the play button over and over.