Treating AR-4x cloth surrounds

[Kieran M]

Hi all,

How often should you retreat the cloth surrounds on the woofers?  Mine were done 10 years ago, the speakers sound fine, just curious. Mine are a pair made in ‘67 refurbished by Mr. Carl Richard in 2009.

Thanks,

Kieran

[RTally]

Do the push test. Push in the woofer, hold for several seconds, and then quickly release. See how long it takes the cone to return to its normal position.

Generally, anything over about 1/2 second is fine, with the better sealed speakers taking more than a second to return. If the cone pops back too quickly, you have a leak somewhere, either the surround or elsewhere.

[Kieran M]

Thanks, I’ll give that a shot.

[JKent]

Hi Kieran and a belated welcome

As a fellow AR-4x owner, I'd say don't do anything!

Here are my thoughts:

• The treatment of the cloth surrounds should last decades. Maybe even half a century.
• The 4x isn't as air-tight as other AR speakers, so the "push test" will give you the false impression that the surrounds need re-sealing. Look at the dust caps. They're porous and meant to be so.
• I see a "possible" problem. Our late friend Carl Richards (one of the moderators here btw) did great work but in 2009 he may have still been using Permatex to seal the woofers. That was suggested in the 2007 AR-3a restoration guide but that was a mistake. Turns out Permatex eventually hardens somewhat. The ONLY sealant that should be used is RoyC's butyl rubber solution but that may not have been available in '09. So the real question may be; how to remove the Permatex.

Sorry. If the speakers sound fine as you say, leave them alone and just enjoy them.

-Kent

[ra.ra]

On 8/7/2019 at 1:27 PM, Kieran M said:

...the speakers sound fine...

This seems to be the most important statement here, so ........."If it ain't broke, don't fix it."

Kent's comments about the 4x woofer are spot-on regarding air passage through the dust cap, and what is normally a rather quick rebound of the cone when doing the push test on this particular woofer. More importantly, perhaps, are the suspicions he raises about the sealant product used on the surrounds. Carl was a very knowledgeable speaker restorer and an extremely generous sharer of information and supporter of this site, but it would still be a good idea to confirm how your surrounds were treated back in 2009. Maybe you post a couple pics here?   

[Kieran M]

Thanks, gentlemen, yeah the woofers rebound immediately when pushed back. And I noticed the very porous dust cap for the first time! I’m outta town but I’ll post some pics when I get back later in the week. 

[lARrybody]

Toluene was the solvent used in the original surround treatment. I used some to condition and clean some AR3a cloth surrounds before I applied some of Roy’s formula. In fact I had a jar that had dried up a bit and I used Toluene to reconstitute it. Had to buy a 1 gallon can, thus a lifetime supply.