Reset all the cables on the back of the silver box - both the RCA jacks and USB. Open the box and check the RCA cable connections leading to outside thru the box. Reseat the connections at the audio board. If you think if might be the woofer alone unplug the yellow RCA jack and see if it makes any difference. If it doesn't plug the red or white RCA jack to where the yellow one was inside the box - if the woofer becomes active replace the RCA cable with the yellow ends (mine was faulty). Under the test menu there is a sound option that should be running while you check this out.