I have two REL Q200 subs, one I bought new, and one secondhand. Unfortunately the secondhand one doesn't seem very well. When I first took possession of it I wasn't convinced it sounded as tight as my other one, and it seems to have developed a definite problem. When pushed to even mild levels, it can now produce an unpleasant "farting" sound at certain frequencies and this problem has been getting progressively worse. My problem is, I have no guarantee for this, so even though REL are happy to have a look at it, it'll cost me an arm and a leg for postage due to the weight. From my rather poor description, does anyone have any idea what the problem might be. I'd appreciate any thoughts on: 1. If it is likely to be worth having it repaired. 2. Is there any chance it is something I may be able to do myself? 3. Any good repairers within a shortish drive of N. Essex? Any thoughts gratefully received.