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Author Topic: Good speaker surround glue? Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 06-10-2009 11:55 AM                     In my earlier post: "How to find a bad driver?" I did find the bad drivers X2. These are EV 15" subs which the cone and cardboard surround have come unglued from the basket edge, thus creating a nice flapping sound at 61Hz. The cone surround and cardboard are still in good shape. It looks like all I have to do is glue it back together. I have installed new surrounds on speakers before using some white glue provided by the company I bought the surrounds from. Does anyone know what the most reliable type of glue is that I can use?  |  IP: Logged Jim Cassedy Phenomenal Film Handler Posts: 1661 From: San Francisco, CA Registered: Dec 2006 posted 06-10-2009 01:53 PM                     This doesn't exactly answer your question but I'm not sure how reliable a 'home made' speaker repair will hold up. I'm not questioning your ablility. It's just my gut feeling about speaker repairs. Since you're located here in Northern CA, I can highly recommend a company called Orange County Speaker Repair, in Los Angeles. They were recommended to me by a couple of local audio techs several years ago when I needed to have some Altecs re-coned. They can do the entire job for you at a very resonable price and if I recall, they also sell kits which contain the proper glue & materials so that you can do an "expert" cone-edge repair yourself. Their web address is: www.speakerrepair.com Check out their website and see if they have what you need. If you decide to have them do the repair, I can tell you I've used them several times and they do excellent work. Turn-around time was amazingly fast too.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-10-2009 03:59 PM                     True. It's best to have the speaker reconed. For if you do it yourself, the cone has to be dead center in the basket, otherwise, you'll have a rasping sound due to the speaker windings rubbing against the magnet.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 06-11-2009 08:16 AM                        I have done a number of these repairs, and I must say, after the daunting first few, it really is a relatively easy job. The cone is held dead center by separators that are supplied which are the exact size of the gap and they hold the coil centered while you apply the glue to the spider. If the surround material is foam rubber, you best use the replacement that comes with the kit because that stuff disintigrates after about 10 years (more or less depending on the harshness of your environment). I know of what I speak because we had 16 speakers ALL with foam rubber surrounds that just fell apart and had to be replaced. The repaired speakers with these kits sound every bit as good as the original and I even think the bottom end is more solid than before. I can drive them to quite hard and there is no sign of breakup or distress. Quite a few years ago an older tech once showed me a treatment for paper speakers that was pretty impressive. He said that you can extend the bottom end response of older paper subwoofers by "doping" them with rubber cement. You paint the entire speaker cone with a coating of the cement as evenly as possible and supposedly this will increase the damping. I've never done it, but he did one while I watched on, and I actually heard the before and after results with its response in the 40hz to 60hz range; where it doubled prior to the treatment as he increased the level, it was able to deliver more sound pressure after the rubberized treatment before it began to double. It was pretty impressive. I would like to have seen a full spectrum chart before and after to see how it affected the overall response, but to the ear it was pretty sweet. If I get a chance I'd like to try it on an old speaker and really seriously test the effect. We've got some old speakers into which it would be nice to be able to pump some new life.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-11-2009 09:11 AM                     quote: Frank Angel He said that you can extend the bottom end response of older paper subwoofers by "doping" them with rubber cement. I wouldn't do that in any theater in this area... the cone would be stuck full of popcorn, candy wrappers, and other items in just a short time period.... Those dam blowers the janitors use.... Mark  |  IP: Logged Robert Minichino Master Film Handler Posts: 350 From: Haskell, NJ, USA Registered: Dec 2005 posted 06-11-2009 10:19 AM                        Adding rubber cement to a paper cone won't help the cone's stiffness (it might even hurt due to the increased mass), but it will retune the speaker so that the resonance is at a lower frequency. The effects on the Thiele/Small parameters of the driver by adding mass: Fs (resonant frequency) decreases by the inverse square root of the mass Q (quality factor, inverse of damping) increases proportionally to the mass n0 (efficiency) decreases with the inverse square of the mass So by adding mass, you get a driver with a lower resonant frequency that is less damped (boomier, looser, etc.) and much less efficient.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 06-11-2009 02:07 PM                        quote: Robert Minichino So by adding mass, you get a driver with a lower resonant frequency that is less damped (boomier, looser, etc.) and much less efficient. That, plus like Mark said, the popcorn stuck to it would have to make it even LESS efficient! Then again, one big explosion and all that stuck popcorn goes flying back at the audience! Hmmmm....amazing what techie myths abound.  |  IP: Logged Jack Theakston Master Film Handler Posts: 411 From: New York, USA Registered: Sep 2007 posted 06-11-2009 02:54 PM                     If the speaker is worth anything, don't risk f***ing with it and take it in to have it re-coned. DO NOT DOPE IT WITH RUBBER CEMENT, ELMURS GLUE or VARNISH (another myth). Many audiophiles recommend this, but in my experience, the added brittleness and uneven nature can and will cause damage over the years. The less weight you put on the cone the better. If you're going to use any glue, use the real stuff- LocTite 410 Prism Instant Adhesive. It's a black rubber-based adhesive that is far more flexible than the other suggestions.  |  IP: Logged Eric Robinson Jedi Master Film Handler Posts: 538 From: Santa Rosa, CA Registered: Jan 2005 posted 06-11-2009 04:09 PM                     I think I'll just send them in for a new surround service to Orange County Speakers. I was just going to glue the loose edges, but, the more I think about it...I don't want to have to work on these again when the surround craps out. Its no fun as you all know trying to remove these from a cabinet way up high with cakes of dust and other unidentifiable materials. The Loctite 410 does look like a good product though. Thanks for the tip.  |  IP: Logged Jim Cassedy Phenomenal Film Handler Posts: 1661 From: San Francisco, CA Registered: Dec 2006 posted 06-12-2009 09:33 AM                     quote: Mark Gulbrandsen the cone would be stuck full of popcorn, candy wrappers, and other items in just a short time period.... Those dam blowers the janitors use.... Hahahahaha- ain't that the truth! One theater I worked at had the sub woofer at floor level behind a skirt under the screen. I constantly found pieces of sticky carmel popcorn the theater sold stuck to the cone. I considered putting a screen over the cone but figured that a metal screen would just resonate at the low freqs. and actually the damn carmel corn would only wind up sticking to either a metal screen or a fabric mesh which I also considered putting in. We moved the sub back a bit and were able to raise it a few inches without having it get blocked by the screen frame superstructure. It wasn't a perfect fix. I'd still occasionally have to crawl under the skirt and brush off the carmel corn or we'd wind up with a carmel cone.  |  IP: Logged

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