I just received a 25-31CS. When I hooked it up to my Carver AV-505 5 channel amp the sound output is very low. Even with the gain knob on the amp maxed out and the receivers sub volume at +10 (maximum). I'm currently using a Sony receiver as a pre/pro. I have 3 other 8 ohm speakers hooked to the other inputs on the amp if that matters. Would a 8 ohm 4 ohm mix (SVS) matter? I'm kind of reaching at this point. I've tried hooking it up to the receivers amp (with the selector switched to 4 ohm) with the same low output. It also has two 8 ohm speakers (rear surrounds) hooked to it. So far these are the things I've tried. -Different subwoofer interconnect -Different amp channel on external amp -Different speaker wire -Tried each subwoofer preamp out(havent tried y-connecting both) -Checked the internals of the sub for damage or disconnected wires. -Have all speakers set to small with subwoofer=yes -Hooked straight to receivers amp with front speakers set to large with subwoofer=no I've probably forgotten a few things I've checked but any suggestions are appreciated.