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Author
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Topic: Speaker Repair
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Don Mogle
Member From: Robins AFB, GA, USA
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posted 12 September 2001 05:10 PM
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I recently found a great deal on an Altec 421-8-H2 speaker at a pawn shop. The problem: it has a tear in the cone. I'd like to give a shot at repairing it myself before giving in to having it reconed. Has anyone out there successfully repaired one. Can you give me some advice? Oh, who out there could recommend some good reconing shops?Thanks. |
Donny Hinson
Member From: Balto., Md. U.S.A.
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posted 12 September 2001 05:55 PM
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Reconing would probably cost more ($85-$125)than the speaker is worth. I have had good success with cone repairs using the following method...1. Cut a piece of thin, strong fabric (an old nylon scarf, or a pair of pantyhose) to cover the tear, extending at least 1/2" beyond the tear in all directions. 2. Coat the the tear, and a 1/2" area all around the tear (on one side of the cone only) with a thin layer (1/16") of RTV, the regular type silicone which is often used for bathroom caulking. USE ONLY 100% silicone...not the acrylics, or acrylic-silicone combinations! 3. Place the fabric you have cut over the coated area, and press it lightly into the silicone by putting your other fingers on the opposite side of the cone (this is why you don't coat both sides of the cone). If the repair extends into the suspension ring (the ribbed area where the cone attaches to the frame) make sure the fabric conforms to the ribs, so that the cone excursion is not affected. 4. Now that you have applied the fabric to the repair area, coat the fabric and the 1/2" area around the fabric with more RTV. Use a thin coat, 1/16" thick is plenty! 5. Allow at least 48 hours for the silicone to cure before using the speaker. I have even used this method to repair a speaker that had tear 3/4 of the way around the entire speaker suspension ring, and then used this speaker for several years. I finally burnt out the voice coil by playing too loud...but the cone repair held! [This message was edited by Donny Hinson on 13 September 2001 at 04:51 PM.] |
Chris Lucker
Member From: Los Angeles, California USA
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posted 13 September 2001 10:40 AM
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Donny,
Have you compared the method you described to the heavy tissue (the stuff that comes in new shirts, etc)and nail polish or acrylic lacquer or spar varnish?
I am not disputing your method. I have two pairs of twelves -- Altecs and Fender CTS's that need repairs and have only seen the tissue repairs in the past. Your method sounds strong!
Thanks.
Chris |
Blake Hawkins
Member From: Land O'Lakes, Florida
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posted 13 September 2001 11:06 AM
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I like Donny's method.
So I'll pass along the following just for reference.
The old time radio technicians would take a ball of cotton, form it into the shape of the tear or hole, saturate it with glue and press it in.
The glue used was a general purpose cement used to fasten speaker cones to the frame.
I don't think this method would work on a high powered instrument speaker.
Blake[This message was edited by Blake Hawkins on 13 September 2001 at 11:07 AM.] |
gary darr
Member From: Childress,somewhere out in Texas
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posted 13 September 2001 02:58 PM
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I have a 15 inch speaker that had become to soft around the cone area close to the voice coil and about three inches outwards. The speaker would make woofing and popping sounds as a result of this condition. I use a poly type wood floor finish and mopped it around the weak area with a Q-tip , speaker works great now even under conditions such as a side fill monitor for our digital drum mix. Have allso repaired tear in speaker using paper towel and poly finish with good results. I suspect the response of the repaired speaker might change some depending on how extensive the repair is but I actually noticed improvement in the case of the 15 inch speaker for the particular application.------------------
sho-bud,session 500,american standard strat,shecter tele,peavy classic 50
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Donny Hinson
Member From: Balto., Md. U.S.A.
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posted 13 September 2001 04:40 PM
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Chris, at one time I tried the lacquer dope that was designed for speaker repair. I found that, while good for quick repairs, it tended to dry and crack with age and use. Also, it didn't work too well on the suspension-ring area, due to its stiffening tendencies. It's almost impossible to do a cone repair, and duplicate the exact stiffness/density of the cone material. In an application where movement and flexing is as profound as it is in an instrument speaker, I prefer a flexible repair over a stiff one. But, the lacquer method would probably be better on very low mass-high frequency applications (like cone and diaphragm-type tweeters). |
Chris Lucker
Member From: Los Angeles, California USA
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posted 14 September 2001 10:21 AM
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Donny,
That speaker repair dope you mention must be the yellowed cracked stuff I often see in old speakers when I am vintage amp shopping.
I am going to try your flexible method.
Chris |
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