I fully agree with both of the last two comments--1) why would you need this in a home system?, and--2) the fewer the components in the signal path, the better. In my welcome post, I mentioned that I have a history with both true audiophile equipment (what you put in is to be reproduced as accurately as possible within the limitations of the room and/or equipment to fully appreciate the original recording), as well as commercial audio for DJs, bands, nightclubs, etc. (what you put in is to be processesed to death to provide bone-crushing decibel levels in volumetrically challenged spaces--i.e., large, with clarity--not accuracy). Sometimes the two overlap so I always keep a full commercial rack operable at home--plus it comes in handy for that last-minute booking for a wedding, party, etc. (Sorry, you can't "scratch" on my Linn turntable or use my Infinity RS-1s and Krells at the bar).
As to what they do, a compressor/limiter/gate can be used for numerous functions from basic protection of speakers and amps from signal spikes (my primary application) to complex effects on individual instrument channels (guitar, keyboard, drum--attack, sustain, decay rates, or vocals--presence).
The BBE Sonic Maximizer is to commercial audio what my Carver Sonic Holography Unit is to my audiophile system. By manipulating delays at different points across the frequency spectrum, it insures that all frequencies arrive at the soundstage together for the desired "sonic image".
