Matt, I just read this thread from top to bottom. I also saw the "woofer pumping" thread, but did not read it in its entirety. However, I have to ask an obvious question: where is your tt located with respect to your speakers? (I am sure this question was asked and answered on the other thread, because Doug would have also been asking about it here if that were not the case.) Anyway, on the off chance that you have not considered this, acoustic feedback from the speaker to the tt can certainly cause this sort of misbehavior. And even if the two components are not in obvious proximity, you might consider re-positioning either the tt or the speakers empirically, because quirky room acoustics can result in feedback even when there is no obvious reason for it. Further I would advise you to figure out your basic problem before installing your new REL woofer, lest you blow another one. You mention that the driver pumping has some sort of periodicity to it. I assume that by now it is established that the pumping only is observed when you're playing LPs, not with other music sources. Have you listened carefully to your new tt, to determine whether it is making a periodic mechanical noise of some sort? (This is what Doug was getting at.) One worthwhile experiment would be to install a different tt/tonearm and observe whether you still have the issue. That would indicate a problem with our new tt. Perhaps you still have your old Thorens or you can borrow a tt from a friend.
