I recently picked up a used rw10 from craigslist for cheap. The issue I'm having is a bit hard to describe.. It's not a blown speaker but the sound is awful. I have all the settings properly configured on my receiver, ran a monster cable line-in to the sub (LFE) and no matter what I do with the frequency/phase knobs nothing seems to change the sound. It just had a muffled, tin-can sound, like it's trying to put out a higher frequency than it's supposed to. The bass is there but its masked with the muffled noise that just drowns out everything else. I ran a bass test and the sub starts to pick up around 200hz. Again if I adjust the knobs nothing seems to change that. Any idea what could cause this? Thanks.