Film-Tech Forum ARCHIVE: Altec Lansing 1698 monitor speaker

This is topic Altec Lansing 1698 monitor speaker in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jarret Chessell (Member # 5077) on 11-02-2009, 04:12 PM:

Has anyone else had this happen? I just turned on the monitor and the foam between the diaphragm and the frame completely detached itself! Last time I turned it on it seemed fine, today, dead. At closer inspection the foam is incredibly brittle. Speaker is an altec lansing model #5385. What do I do now? [Frown]

Posted by Ian Parfrey (Member # 5122) on 11-02-2009, 05:46 PM:

Jarrett.

Sounds like you have a case of "foam rot". I have had many foam-surround drivers of all breeds suffer from this and the only remedy would be a recone with a doped surround cone preferably, or a foam one should the doped cone not be available. These are the ones with the latex (I think) covered corrugations around the cone itself.

Recone kits should be available fairly readily.

Cheers
Ian

Posted by Tony Gallimore (Member # 5358) on 11-02-2009, 11:01 PM:

I've run into foam rot a couple of times so far. The last one looked like bugs had eaten the foam away leaving trails all through it. Since the voice coil usually deteriorates with use as well, I usually have the voice coil, cone and all replaced. There are several companies here in the lower 48 that rebuild speakers of all sizes and do a pretty good job. Dixie Speaker Repair Company in Birmingham, Alabama did the last one for me for less than a hundred bucks. The speaker was a 15 inch woofer.

Posted by Cameron Glendinning (Member # 3516) on 11-03-2009, 01:36 AM:

Yes its "foam rot", you don't need a recone, just replace the foam with a similar foam. Many companies will do it for you or will supply you with a foam and glue to DIY. Foam is the best surround material but has the most limited lifespan. It is not recommended to use a longer lasting rubber surround replacements as this will change its response.

Altec speaker gear will have matched parts through great plains audio (.com) web page I suspect.