Speaker surround goop?

[barkingdog]

I recently picked up a pair of reconed EVM12L's on eBay for some floor monitor wedges. One of the paper surrounds looks "normal", the other one has a mesh-like paper that looks like you could spit through. I'm guessing that this is what the surround looks like before "goop" is applied.

My first question is, are the speakers usable without the goop or does the goop reinforce the folds in the surround?

My second question is, what is the "goop" that is applied to paper surrounds, how can I get my hands on some and is there a suitable substitute that would be readily available in a hardware store?

Thanks in advance.

[Zilch]

Use "Search" to discover more than you ever wanted to know about "Goop."

[barkingdog]

Thanks Zilch. I did that and came away with no more understanding than when I started

I saw such things as "AA75 Waldom", "Bituthene Mastic" and "Cyanoacrylate". I'm pretty sure that if I ask for any one of these at my local hardware store I'll get the deer-in-the-headlights stare.

Can you narrow it down for me? Thanks.

[barkingdog]

If I understand correctly, we're talking about "doping" the edge. So, to ask a more specific question .... what can or should one use for the doping of a paper speaker surround? (suitable substitute question still applies)

[scott fitlin]

The original surround doping goop used was called Airflex, and is no longer available.

You will have to either talk to the speaker manufacturer or a reconer to find out what is an acceptable substitute.

[edgewound]

If I understand correctly, we're talking about "doping" the edge. So, to ask a more specific question .... what can or should one use for the doping of a paper speaker surround? (suitable substitute question still applies)

Airflex is a polyvinyl acetate that seals and damps the cloth surround.

An Authorized EV reconer in your area should have some on hand. It sounds like the one you got from eBay might be aftermarket recone, since it has no damping compound on it.

Without it applied, the surround will leak air and also resonate at its resonant freq.

[moldyoldy]

...It sounds like the one you got from eBay might be aftermarket recone, since it has no damping compound on it.

Yup, used an OEM EVM-12L kit awhile back, it was pre-doped, but didn't look like Airflex or the gooey Altec dope I've used.

The only product available to consumers I know of is the white latex used also on refoams. Never tried it myself for doping, but I think it would be OK if applied only heavy enough to close off the mesh. The goal is to seal air passage through the surround, while altering the compliance as little as possible. Backlight the cone with a bright bulb, and you can easily tell when you've done enough. Let each pass dry (20-30 minutes) before making another.

Or, go to an EV center as Edge said, to get it done right, just expect them to want to sell you a kit of their own. I'm a little more tolerant of aftermarket kits in MI apps, and have heard a few I preferred to the original, you just never know till you go there. The one I did with the factory kit ended up in my Marshall, and I think it'll stay, and I've had the Celestion and a 417 in there before it I wasn't as happy with. YMMV.

[edgewound]

Yup, used an OEM EVM-12L kit awhile back, it was pre-doped, but didn't look like Airflex or the gooey Altec dope I've used.

Sounds like it was an RDM cone with their "plastiseal" pre-treated surround. Usually, those cones are supplied with an EV cone kit that goes into a driver/system employing "Ring Mode De-Coupling" with a bead of silicone damping in the surround rolls/pleats.

This thread should be moved to a non-Lansing area.