I just finished connecting a 5.1 setup to a HK 435 receiver. All Ascend speakers have output except for the HSU VTF-2 subwoofer. Thinking that the subwoofer cable was defective, I purchased and connected a different cable, but this too did not fix the problem. I've gone through all of the receiver menu items to verify that the subwoofer was in fact turned on. By using the "TEST" button on the HK remote, all of the speakers receive and play the test tone, except for the subwoofer.

Any thoughts on what I might try, or what the problem might be?