I have two B&W subwoofers in my listening room. One is fed by an AQ Sub-A and the other by an AQ Sub-X, both approx the same distance in length. I honestly cannot tell the difference. I've tried to tell but can't No real need to spend anymore than this level. I've got more tight and clean bass in this room than I 'll ever know what to do with. Don't go nuts spending a fortune on sub-woofer ICs. The big plus with AQ subwoofer cables is that 3rd ground wire connection for eliminating hum. That truly does work and it's completely eliminated the hum I was experiencing.