My first speaker repair

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Mongoose

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This is not a tutorial of any kind, just thought I would share it here. I had these original Mercedes speakers lying around, both of them with foam surrounds that have gone all soggy and deteriorated over the years. These units came out of the front doors of a W210 E class and where replaced buy after market cheapies. The problem with the cheapies, was there inefficiency compared to the original speakers. After quite a few Youtube videos, I decided to give it a go and replace the surrounds.

I wanted to spend as little on this as possible and wanted to use what i had at home. I approached Azam of Speaker Repairs out in Wynberg and got two 6 inch foam surrounds and some contact glue at the local babie shop. Forgot to buy a small paint brush and ended up having to use ear buds to spread the glue. So all in all, two surrounds, super small tin of contact glue and three earbuds and a super small scrapper I had lying around. :goofy:

I never took any pics of the speakers before I removed the surrounds, but got this one after I removed the surround

This image shows the new surround on the side
IMG-20191123-193503-resized-20191124-092705519.jpg


IMG-20191123-193500-resized-20191124-092706382.jpg


Was a super simple matter of scrapping the old soggy surround off from the plastic frame, and carefully removing it from the cone. Luckily for me I already had the markings of where I should apply the glue. This will not be the case should you have a brand new cone fitted.

Prefit
IMG-20191123-193518-resized-20191124-092705717.jpg


Anyway, a thin layer of contact cement was applied to the rim of the cone, and gently put the new surround in place. After a minute or so, I gently centred the surround and applied finger pressure where the glue was. Care should be taken to not apply contact glue directly to that actual foam surround, it causes it to warp. Now for the second and tricky bit.

To get the surround on to the frame, without shifting the voice coil centre. Azam suggested I use a low frequency tone generator of some soughts and play a low frequency sign wave of between 10-20hz through the speaker, at very low volume. I opted for 30hz, pls dont ask why. With glue now applied to the frame, it is time to set the foam surround making sure the voice coil is centred. So put an imaginary cross on top of you speaker, this will give you four points. Play the low frequency signal at low volume, and using the four points of your imaginary cross, systematically apply pressure to the surround and frame. If that makes any sense  :giggle: Trick is, you have to listen for any scrapping of the voicecoil against the magnets pole piece. If any scrapping is heard, you have to tug or move the surround on the opposite side of the cone. Kapish! to be honest, I found it a bit annoying to use the tone, and with the second speaker I did it by not using it. Azam as well as Youtube suggest using pegs as you go along so as to hold the surround in place. I couldnt due to the lip that this speaker has.

And here it is, all done and no scraping at all. Super chuffed to say the least, and it only cost me a small tin of glue.

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I could have avoided those nasty looking glue marks on the side, if i had bought a small paint brush. These speakers are so much more sensitive than the cheapies that when in there. To get a balanced sound, I had to set the fader to plus 4 for the front speakers.

Again, not a tutorial, but feel free to use it as one. By the way, Speaker Repairs in Wynberg has a range of spares for various speaker. Including but not limited to voice coils for B&W tweeters, red surrounds for Cerwin Vega drivers.
 
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