Underneath the smoked glass of the B212 ultrabass sub there is a square shaped piece of material (not sure if it is foam rubber) seems to be somewhat disintegrating and discolored. These speakers were bought new 37 years ago. Can anyone who may have owned or now owns L212's give some insight as to what the material is and where I could go to get it replaced? It still has the JBL badge in the bottom right corner. Looks like a small cut out that the badge presses into. As I mentioned in my post a couple of weeks ago everything else seems to be in pristine condition. I was able to get my 066 tweeter repaired which was unexpected so all is good.
Thanks in advance to anyone who can be of help with this.