Polkaudio I-Sonic Entertainment System Four-speaker I-Sonic technology delivers a room filling, stereo all-around soundstage 360-degree around the entertainment system. You will hear big life-like sound everywhere in the room, even if you are to the side or behind the unit + Rich sound with bass-port technology Treble and Bass tone controls to customize sound delivery DSP - Dynamic Loudness Contour automatically adjusts bass and treble response to account for your ears' frequency sensitivity at low volume. You'll hear rich well-balanced sound even at late night listening levels. The DSP also prevents distortion at high volume with its Dynamic Compression. Go ahead, crank up the volume and play air guitar to your heart's content HD Radio technology for static-free reception. Radio stations all over the country are converting to digital HD-radio broadcasting. The chances are very good that your favorite radio station is or will shortly be broadcasting in HD If your favorite radio stations are not yet broadcasting in HD you will receive standard analog AM and FM just like ay other AM/FM radio (only better sounding of course) / Up to 30 station presets