Audyssey Room Correction (EQ) is an increasingly popular feature that can be added to home theater receivers and AV preamps.  The idea is to use internal chipsets and DSP paired with a microphone to employ processing in multi-channel EQ to fix room acoustic issues, with the goal of making a better-sounding home theater experience.

The highest level of Audyssey EQ requires a professional audio calibrator to come out and fine-tune the room. The MultEQ system found in receivers like those from Denon and Marantz goes a long way towards making any room sound better.

Also check out Anthem's version, ARC, as well as the Trinnov system found in Sherwood receivers like the R-972.