I use EQ on my system and would not be without it. My EQ is all digital. I use a BFD on the sub and have it flat within +-1db! The parametric EQ allows to correct for the room response, eliminating boominess. Some people create a house curve to satisfy their tastes (I like it flat...once you have listened to a flat bass response for a few days, it is hard to listen to anything else). My other speakers are adjusted using digital 31 band EQ's. The adjustments are very subtle, and tame certain undesireable artifacts such as honkiness, tinniness, or the ever unpopular shrillness in women's voices. To be fair, since I bought my Epic 80 system, There is pretty much NO EQ given to the speakers. They are quite close to flat in my room. Just simply a half decibel here or there (a 1/3 octave EQ is not quite as precise as a parametric, so small adjustments are needed to keep it from affecting adjacent frequencies).
One last thing. When I say the bass is flat, I mean that it took me several hours to measure from 15hz to 120hz, 1hz at a time. Then I had to plot the results, find my center frequencies, decide on my bandwidth, correlate that to the BFD number system, and program it all into the BFD, along with the cut or...in one case, a mild boost. Then the delay that is added by the digital EQ's must be factored in and adjusted to keep time alignment correct. It is a slow process with gratifying results.
