Like Don said I think todays higher end powered speakers have something similar built in. The BBE's are amazing though. I used to set up my PA for someone and ask them how it sounded. I'd ask more Treble, Bass ?? No, it sounds fine. Then I'd kick in the BBE and they would be blown away. Put a few on Hammonds too using an effects loop off the preamp. Also a big WOW. Gives the impression of more volume too. I know guitarists use them also.
Bill in SC --- Roland BK9 (2) Roland PK5 Pedals, Roland FP90, Roland CM30s, JBL Eon Ones (2) , EV mics, Apple iPad (2) Behringer DJ mixer