As previously noted in this space, I’m a deranged audiophile, and for some years my speakers of choice have been from Totem, out of Montréal. In a recent renovation a woofer got a dent in a dust cap, where by “dent” I mean it was pushed in. I’m posting the solution here in the hopes that future searchers will find it.
I was sitting up late listening to Coltrane and something about the sound just wasn’t gelling. Eventually it bothered me enough to turn on the lights and even then it took a while to spot the problem, illustrated below.
The round thing in the center of the lower driver is supposed to be smooth and convex, not uneven and concave.
There’d recently been a renovation that’d required moving the speakers out of the way; I can only conclude someone applied a blow with their butt or knee.
At first I thought the driver was ruined and I was sad, because these speakers have made beautiful sound for us for years. I called the local Totem dealer to consult and they said yeah, they could replace the driver, but it sounded like it was just the dustcap, why didn’t I try just pulling it back out?
Easier said than done; getting a grip on a smooth curved surface is harder than you’d think. We tried Blue Tack. We tried duct tape. We tried the locking suction cup that holds up the bag of bath toys. The problem is that with many of these options, to get a grip you have to push down pretty hard, which is probably not good for the music.
Enter the wizard · By which I mean my practical, innovative spouse Lauren Wood, who’d already had a couple of good (albeit failed) ideas. She furrowed her brow and said “I think hot glue will do it, but it feels a little drastic. I’ll give you a few minutes to think about it.”
I couldn’t think of any other alternatives, so why not? What she did was get out the vacuum cleaner, take the end off, and hot-glue the vacuum pipe to the dented dustcap. The combination of the glue and the suction gripped pretty hard. The cone resisted smoothly but strongly as she pulled, but I don’t think it ever came out as far as I’ve achieved on those occasions when the family’s out and I crank up the Led Zep. Anyhow, in just a few seconds, hey-presto, it was smoothly convex.
Well, and festooned with gobs of glue. But that’s OK, hot glue peels off pretty easily, at least before it’s had a while to set. The dustcap is back to the right shape and, while it has a few little scars if you look close, I call them wounds of love. And Coltrane gels just fine now.
Comment feed for ongoing:
From: Fazal Majid (Apr 11 2016, at 15:58)
You have it easy. My 4 year old daughter has taken to pulling off the magnetic grille from my B&W 804S tweeters and poking the tweeter dome. I figured out how to un-dimple them by dismantling the tweeter assembly and popping the diaphragm back using a Q-tip and no small amount of trepidation, but after a couple of times, metal fatigue is setting in and I guess I will have to spring for expensive replacements.
Speaking of Coltrane, did you know there is a church here in San Francisco who reveres him as a saint and prophet for "A Love Supreme"?
http://www.coltranechurch.org/
Unfortunately they are losing their lease (SF rent explosion in action)
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From: Jeremy (Apr 13 2016, at 03:23)
I've used the vacuum cleaner trick before on woofer dust-caps - never needed (or thought to use) any other adhesive.
Tweeters are a different story...
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From: Chris (Apr 15 2016, at 03:54)
I've just restored a beloved, but old, Richard Allen subwoofer. The foam around the drivers had disintegrated. I got a refoaming kit from eBay, and 2 hours of work, and two overnight drying periods later, the subwoofer sounds better than ever! I reckon the foam had been disintegrating slowly over the years and the sound was gradually, but irreversibly, dying!
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From: Amlan Chatterjee (Apr 21 2016, at 19:31)
Tim it was nice chatting with you today. Funny that I had the same issue with my B&W 804N tweeters. I tried two sided tapes and gently pulling out and then the dismantling and Qtip approach as well. But it was still not exactly right and my OCD was in full force, so I just ordered the front tweeter assembly from B&W. Thankfully they sold just that. Cost me $100. That went well, till I noticed this micro dot on the tweeter diaphragm on the second tweeter........
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