Nine Class-D digital amplifiers perfectly tuned to match the nine dedicated speaker drivers and the acoustic architecture. Three tweeters create the crispest and clearest high-frequency response. Six mid-woofers give you the full range of sound effects and music from the left and right channels, and crisp, clear dialog from the center. Mid-woofers act together as a phased speaker array so what you hear matches what you see on screen. Optical input to connect to your TV. Allows Playbar to speak DOLBY DIGITAL and stereo. Adjustable bass, treble, and loudness controls to customize your sound preferences. Autoplay setting lets you choose whether or not TV audio will begin playback automatically.