So I was practicing a little while ago and I noticed that my bass response was becoming more muffled and there was some slight distortion. Freaking out, I unplug everything from the wall, take out all the connections, and start unscrewing the grill fearing the worst... .... only to find that the foam rings had started to decay and were not adhering properly around the speaker. I pressed them down with a bit of force and got them to stay, and that seemed to have remedied the problem until half an hour later when they came off again. So now for my question - which replacement rings should I buy and/or what kind of adhesive or glue should I use to hold them in place? The cab in question is a SWR Goliath Jr-III (pre Fender) 210.