After hearing a friends' PSW 450 sub, I had to have one. Problem is I had to turn the back volume knob up to 80% of the range to get decent bass. I also heard loud cracks or pops when played at loud volume. I normally don't play DVDs loud but the Matrix is an exception. The folks at Polk were courteous as usual but they wanted me to send in the 10" woofer. It doesn't appear to be blown, however. Anyone have any ideas?