VIZIO SB4051-D5 Smartcast 40&rdquo; 5.1 Slim Sound Bar System True 5.1 listening: enjoy 5.1 Surround sound with the included rear Surround sound speakers and wireless subwoofer Download the VIZIO Smart Cast app to turn your smartphone or tablet into a powerful touchscreen remote. Simply tap the Cast button from 100+ audio apps you already know and love to start playing on your sound bar. 101 dB of room filling, crystal clear sound with less than 1% total harmonic distortion