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Speaker cone repairs


bruce

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I have a HZ International SB300 sub cabinet. It's one of those 12" dual-coil jobs which you power from both sides of your power amp, with onward feeds to a pair of tops.

 

Anyway - it's started to buzz a bit. On closer inspection there's a tear round the edge of the suspension, currently around a third of the circumference.

 

Questions: Can these be reconed or repaired? Is is a DIY or pro job? Is it cost-effective? Can anyone recommend any repairers or sources for parts? Should I chuck it away and start again?

 

Bruce.

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Yes, it's cambric. Never heard that word before.... (but it's now in the wiki...)

 

I was wondering if the cambric - which is becoming very brittle - could be replaced by foam? There are a couple of places which offer a "large roll" and "extra-large roll foam specifically for subs - eg http://www.speakerworks.net/surround_info.html

http://www.speakerworks.net/surround_rolls.jpg

 

Any thoughts?

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I was wondering if the cambric - which is becoming very brittle - could be replaced by foam?

No. You'll alter the electro-mechanical properties of the driver too much, including its power handling capability and its frequency response. Have a look at 'Thiele Small Parameters'.

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An update. Have sent emails to a number of places, including the original manufacturer and a couple of re-coning people - including wembley (see above).

 

All were extremely helpful. One of the re-coning places I contacted could not help, but referred me to someone else who could do so. Wembley provided me with a price for a recone. And the original manufacturer provided me with a price for a replacement driver.

 

The complete replacement driver is about 30% cheaper than the recone. Which I found pleasantly surprising.... :)

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The complete replacement driver is about 30% cheaper than the recone. Which I found pleasantly surprising.... :)
I understand what you're saying, but I still find that vaguely depressing. :( But then I will always try to fix something broken, whatever the economics.
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The complete replacement driver is about 30% cheaper than the recone. Which I found pleasantly surprising.... :)
I understand what you're saying, but I still find that vaguely depressing. :( But then I will always try to fix something broken, whatever the economics.

 

My ulimate BODGE which I use to get myself out of trouble when the box is needed that day ....

 

Use "J" cloth and evo-stick impact adhesive to repair around the tear. The J cloth and the evostick are both flexible enough to take the movement of the cone. Not very pretty ( a black marker pen can hide the worst!) but has saved the day a few times.

 

Does seem strange that the re-cone is more expensive than a replacement driver?

 

.p.

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Does seem strange that the re-cone is more expensive than a replacement driver?

 

Not really!

 

Whe re-coning, you need to get the cone/coil assembly exacly aligned in the chassis and held there while the glue dries - a difficult job (hence DIY re-cone not recommended). The best way to achieve this is using a jig assembly - just like the manufacturers - who, incidentally mount a hell of a lot more cones in their frames than a re-coning company - economy of scale out-weighs cost of frame and magnet!

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But I can buy a re-cone kit for a Fane driver for roughly 40% of the original driver cost and even with labour at a re-cone company it still only comes to say 60% of the original cost?

Is it down to some companies hiking the price of re-cone kits ? I`ve tried to get kits for PHL drivers in the past and they were astronomical and took forever to arrive?

Yeah maybe the economy of scale comes into the equation but individual kits shouldn`t be nearly the same price as the original driver..?

Re-coning is not that difficult yourself , just time consuming and you need a few special tools ( signal generator that can give a very low hz to test for rubbing is the best one).

 

.p.

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Another option is a service replacement, ie a speaker that has been returned and repaired then sold again.

 

For instance I had a damaged 12" driver for an Apogee AE5 a re-cone kit was about £120 +vat plus labour if done by Apogee a new driver about £450 +vat and a service replacement £190+vat (you give them the old driver)and all genuine parts not some cheap knockoffs.

 

So service replacement not a bad deal, and has manufactures warranty.

 

 

 

Ian

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  • 1 year later...
Have sent Wembley Loudspeakers an email. Hopefully they'll be able to help.

 

Has anyone tried the DIY speaker-refoam kits? Something like http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...item=9711468795

 

I have tried the surround repair kits from Ebay, frankly it's hard to get them properly aligned, and I have yet to figure out how to press up from the rear of the cone on Bose drivers, which have a slotted basket with zilch space for my fat fingers to get through. Consequently the adhesive tends not to stick all the way around, and you (read "I") end up with a set of off-centre flappy surrounds. So, in answer to your original question - I have, and they weren't 100% succesful for me :)

On another note - I contacted Wembley Loudspeakers a while ago with a view to having 8 of my drivers (Bose D11A from 802's) reconed/repaired. They suggested that I bin them and buy new ones from them at £80 each!.

Now, being a Glaswegian, I am not inclined to trash them, so if anyone knows any other repair company.........??

PLEASE???

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