[jcsperson]

Or perhaps, rebutyl question.

I just picked up three Tannoy System 800 Studio Monitors at my local Habitat ReStore for $40. These aren't mine but they look like this:



One of the cabinets is kinda rough and two of the woofers need to be refoamed. I figured between the three speakers I should be able to cobble together two that work well enough. They're just going to be workshop speakers.

I spent the last couple hours combing the internet to find OEM or high-quality exact-fit surround replacements to no avail. Here are the dimensions.



A:  197mm/7.75"
B:  163mm/6.75"
C:  153mm/6.0"
D:  140mm/5.5"

I can get close, but all the smallest measurement "B"s are at least 7", not 6.75". That would mean I'd have a 1/8" "shelf" all the way around between the edge of the rabbet and where the roll ends. (Does that make sense?)

It doesn't seem to me that should matter too much.

Any opinions from the experts?

[dB Cooper]

I refoamed a pair of original Advents and it involved removing and replacing the dust cap. You had to insert spacers around the voice coil assembly to hold it in position while replacing the surround. I imagine the coax tweeter would add complexity to the task. Woofers look like polypropylene which I've heard is tricky to work with.

I would definteky contact Tannoy. They're the real 'experts' in this scenario. They may even have exact-fit OEM replacements.

[AVnerdguy]

The System 800 Monitor woofers use a rubber style surround - The LF unit uses a CNC precision injection moulded polypropylene cone, terminated by a nitrile rubber, high-compliance surround. Typically these never have to be replaced as they do not suffer "foam rot" common to hif fi speakers. Butyl woofer surounds are more difficult to replace than foam style due to the precision required and rarely needed except when damage has been done such as poking a hole through the surround. This would explain why you cannot find an exact replacement. Complete replacement drivers are no longer available. Depending on your application you can substitute a similar woofer

[2wo]

Hard to tell from the photo how bad the surrounds are. If it just a few holes and you are using a shop speakers you may be able to patch than up with rubber cement and if you need a patch maybe a piece  of rubber glove or thick balloon...John   

[jcsperson]

Hard to tell from the photo how bad the surrounds are. If it just a few holes and you are using a shop speakers you may be able to patch than up with rubber cement and if you need a patch maybe a piece  of rubber glove or thick balloon...John

That's a pic I just lifted off the internet. Mine are a bit rougher.

I have one speaker that is completely intact. I tested it and it sounds great. The second one is as you describe; it has a hole 1/4" in diameter almost as if it was pierced by a pencil. The third was completely split all the way around. I thought about trying to find some patching material for the hole. Maybe I'll try that first.

[AVnerdguy]

Typical of a monitor used in road work. The rubber surrounds were more durable for the intended environment but you can't protect them from physical damage such as you described. The tear around the entire surround sounds like it was severely overdriven and a small rip became a large "issue". Lightly press evenly on the center of that unit and listen/feel for any rubbing or sticking of the cone/voice coil material before attempting repair as it may save a lot of time and effort for a blown assembly.

Yes, you can try patching the 1/4" hole. As long as these will be shop speakers and not driven to excessive volumes typical of sound reinforcement installation a small patch will be satisfactory. I've used bicycle tire patching kits for this purpose. The material on the surround is very similar to a high pressure inner tube and the patch material should be a thin as possible. Try testing the glue on a small spot of the destroyed woofer just to ensure that it will not adversely affect the surround. I suggest removing the woofer to allow applying pressure from the rear of the surround while patching from the front. Overlap the hole/tear by approx 10% and avoid excess material that will cause the woofer to move off center when playing lower frequencies .

[jcsperson]

Nerdguy, I'm going to try some different things. One is to repair the damaged surround as you suggest. I found some flexible silicone glue and I'll try to find a suitable patch. I hope I have something lying around that will work.

If that fails I also ordered a cheap $6 Chinese surround off eBay. The measurements are close, but not perfect. If it's a no-go I'll use it for patching material for the torn original surround.

I also lucked into this on eBay, a NIB OEM recone kit. It didn't show up under "Tannoy System 800," but I found the part number in a user's manual I found online and lo and behold, this popped up.

[AVnerdguy]

Excellent! Great find.