Originally Posted by
mumbles
There have been volumes written on this and similar topics by people waaaay smarter than me, so I'm certainly not going to sum it up here. But, regarding signal manipulation, I think it has to do with "how" you EQ more than "how many times". For example, it seems to be "generally" accepted that boosting a signal via EQ is more detrimental than cutting a signal... when you introduce energy into a signal by boosting, you also introduce phase shift which becomes counter-productive to what you are trying to accomplish. There are tons of variables that come into play, speaker size, distance from the listener, early/late reflections, the volume of your interior, etc... hell, what makes one speaker sound different from another?
I know I haven't answered your question really, but if you've heard the phrase you quoted, you've probably also heard that installation is everything. Meaning that the more work you put into the proper design of a system to begin with, the less you will have to EQ the heck out of it later on.