Okay. I got another subwoofer and concluded that my receiver works just fine. The problem is with my Klipsch sw-450. Unplugging and re-plugging the power cable may sometimes work, but an easier way is actually Unplugging and re-plugging the audio cable behind the subwoofer. Sometimes I have to do it multiple times, but it eventually works. I tried with multiple cables and again concluded that the problem is the subwoofer, which seems to not be able to "wake up" from its stand-by. When I unplug and re-plug the audio cable, it causes a "bump" sound and the subwoofer starts working. Interesting enough, if a movie pass through a quiet moment (no bass/low sounds), the subwoofer goes back to the stand-by mode (blue LED is still on) and won't wake up until I cause another "bump" by unplugging and re-plugging the audio cable.
Suggestions are very appreciated.
Thanks,
Lab
