M-Audio Revolution 5.1 High-Definition Surround Sound Card SRS TruSurround XT and SRS Circle Surround delivers incredible suround sound Control panel for bass management and other features DTS output and Dolby Digital 5.1 decoding using third-party applications Game support with Sensaura, EAX, DirectSound and A3D Digital out transmits PCM, plus passthrough of AC-3 and DTS(coaxial)