Polk Audio Surround Bar 9000 IHT 8-channel Amplifer Each of the five mid-bass drivers and each of the three tweeters is driven by its own dedicated amplifier channel for greater dynamic range and clarity Digital Sound Processing (DSP) Optimized Center Array (OCA) Dolby Digital DTS Decoding for 5.1 program material as well as 2 channel stereo Polk Digital Logic, a proprietary DSP program, controls our SDA surround technology to an even finer level, ensuring strong image localization cues and a greater sense of ambience and space no matter the shape of the room