Hi, new here, have question about my receiver which is not outputting signal via digital subwoofer port. My equipment: 4 Polk monitor 50 towers, Polk csi25 center channel, 2 Polk psw10 subwoofers, Yamaha rx-v477 receiver. (all audio is being processed through HDMI with the exception of ipod hookup through stereo) My subwoofers are split off of the digital output on the Yamaha, in the last week or 2 I have noticed subwoofers not outputting. Have worked before, just didn't notice much because the towers do offer a range down to 57hz. Is it a receiver setting? Tried hooking up one sub then the other straight to the receiver, same problem. Replaced both subwoofer cables, no change. I have tried all available sound modes. Now I may have changed a setting (I do play around with them a bit) that has caused this but I cannot figure it out.. Help?