In our last episode we replaced the interior anti-reverb insulation in the speaker cabinets of our classic Tannoy PBM-8 studio speakers. After that step of the project I moved on to replace the deteriorated foam rings around the speaker cones.
These rings are glued to the frame and to the speaker cone itself. They do any number of things, not the least of which is to help hold the cone in the proper position. When these rings age, they fall apart and the result is that the speakers make all sorts of terrible noise.
Replacing the rings is fairly easy, but you have to take your time and get it right. I use the rings from Simply Speakers and follow their very good instructions. Videos are on their site, and I strongly suggest taking a look yourself before you try this.
The photo here shows the speaker ring partially attached. It is glued to the frame, but not to the cone. When both speakers were re-foamed they came out rather well, if I do say so myself.