I have the exact same problem. I bought the Sub-10 just over a year ago, last night I tried watching a movie and was getting no bass. The sub was powered up, but no sound. I too tried another receiver, another cable, checked the fuse, and nothing. This morning while messing around with it some more I was able to get some "buzzing" for bass sounds if I turned the gain all the way up, but that was all it could muster. I'm assuming this sub is still under the 2-year manufacturer's warranty... I guess I'm going to pursue getting it fixed under the warranty... I don't have any other ideas at this point.
Jon