SDA2A passive bass driver question

I uploaded an image of my 1986 SDA2 (SDA-2A) speakers that I inherited from my father several years back, and taking off the grilles (probably for the first time), I noticed bubbling on the foam disk that covers the left speaker driver. It looks like it got warmed up from a heat register where the speaker was situated for over 3 decades (and I guess no one noticed) then started coming off. It also looks like there is a gap where the tacky glue should have been, so I'm presuming it came from the factory poorly assembled.
I want to replace the foam disk (I presume it is a damper material), but have no idea where to get a replacement or buy a roll of the material. Not sure what it is called.
I didn't want to attempt removing and re-gluing w/tacky glue as I'd probably tear it in the process.
Not sure what would cause this - the speakers were indoors the entire time and installed in my father's media room (with the "Maxell" chair - if anyone recalls that commercial from the 1980s) where kids were not allowed (so I don't think anything was spilled on it - no evidence of that). The heat register was 1ft away, though, possibly sunlight beaming into the room could have done this.

If anyone knows anything on fixing this, I'd appreciate it! Thanks!

4331y94vs7a2.jpg

Answers

  • F1nut
    F1nut Posts: 51,655
    Remove the PR and look for an SWxxx number on the back of it. I may have a decent one I would sell you.

    As for fixing what you have I have no suggestions as I've never had to do one.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • pitdogg2
    pitdogg2 Posts: 26,915
    If it is the foam like material on the passive many had the same issue. I've had a pair that did the same, it never got any worse and didn't affect function. It does however like like crud. Polk fixed the problem by using a plastic like cover on the next generation of passive radiator.
    The number may be SW120 or 121