A:Answer Check the subwoofer, if powered, be sure it's plugged in and turned on. Also, notice that there are two subwoofer outputs on the back of the receiver. If one doesn't work, try the other one, and make sure the receiver recognizes that a subwoofer is present, otherwise it may not send any sound to that channel. Try using the "AccuEQ" sound calibration system too. Hope that helps.