EQ is best set "by ear", for instance, twiddling the bands and listening to the result and seeing if you like it.

Well, actually, it is best set using an RTA (Real Time Analyzer) but since a really good one of those will set you back about $1200 and will likely only be found at a higher-end stereo shop, I can't really argue with you!

However, there is one caveat to setting "by ear": you can only do that for a surprisingly limited time (about 20 minutes, in my experience) before every change you make starts making the system sound much better than it was. Better, that is, until the next morning when you hear your tweaked system with "fresh" ears, and can't believe how badly you have messed it up!

My recommendation is to listen to it for a few days, a week, whatever, until you can decide in your mind that, for instance, there is too much bass, not enough treble, but the midrange sounds about right. At that point, without audio playing, go to your EQ settings and bring some of the bass bands down, bring some of the treble bands up, then listen to it for another few days until you decide to do something else. Over time, you'll reach a sound that pleases you.

This is what works for me. Others may have better results doing it differently.

tanstaafl.