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KLH speakers reference thread (original models/Henry Kloss era) 1957-1977

Be very careful with KLH and AR cloth surrounds. My advice is not to add sealant because virtually everything I've tried will stiffen the surround and you will lose deep bass response. The best sealant was sold on ebay by Vintage AR, but I checked this evening, and he is not currently listed. Most surrounds don't need to be resealed, and even if you have a leak you're better off leaving it as is. The materials commonly mentioned like Alene, etc., are glues that will stiffen the surround and will reduce deep bass response. You're better off with a leak. If I find something that seals without stiffening, I will post it here.

A little more KLH history. Henry Kloss co-founded KLH in 1957 and left in 1967, when he started Advent to develop the large screen TV. Every KLH product from the Model One to the Model 27 was either his direct design or under his direction with the exception of the Model 23.

In 1968 I proposed a product to fill the gap between the Models 6 and 5, which became the Model 23. As most of you know, it uses the Model 5 woofer and tweeter, which were designed by Henry, and I did the voicing. Voicing is a design process that determines the sound of a speaker.

Before the Model 23 went into production, I left KLH to join Henry at Advent where I voiced the Advent Loudspeaker. As a result I never heard a production KLH 23. When I discovered AudioKarma a few years ago and read how so many of you like the KLH 23, I bought a pair. Fifty years later I finally heard a production pair for the first time, and I was very pleased!
 
700K said:
Be very careful with KLH and AR cloth surrounds. My advice is not to add sealant because virtually everything I've tried will stiffen the surround and you will lose deep bass response. The best sealant was sold on ebay by Vintage AR, but I checked this evening, and he is not currently listed. Most surrounds don't need to be resealed, and even if you have a leak you're better off leaving it as is. The materials commonly mentioned like Alene, etc., are glues that will stiffen the surround and will reduce deep bass response. You're better off with a leak. If I find something that seals without stiffening, I will post it here.

A little more KLH history. Henry Kloss co-founded KLH in 1957 and left in 1967, when he started Advent to develop the large screen TV. Every KLH product from the Model One to the Model 27 was either his direct design or under his direction with the exception of the Model 23.

In 1968 I proposed a product to fill the gap between the Models 6 and 5, which became the Model 23. As most of you know, it uses the Model 5 woofer and tweeter, which were designed by Henry, and I did the voicing. Voicing is a design process that determines the sound of a speaker.

Before the Model 23 went into production, I left KLH to join Henry at Advent where I voiced the Advent Loudspeaker. As a result I never heard a production KLH 23. When I discovered AudioKarma a few years ago and read how so many of you like the KLH 23, I bought a pair. Fifty years later I finally heard a production pair for the first time, and I was very pleased!
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Very nice. Yes I knew the 23 wasn't a direct design of Kloss. So far as surround sealant I've had good success with Permatex high tack sealant thinned down with laquer thinner to a watery thickness and only apply 2 very thin coats after a thorough cleaning. I only reseal the cloth if it looks like a screen door held up to light and i also reseal the speakers to the cabinet using pure silicone adhesive. My 24's were resealed over a year ago and are still tacky and as pliable as the week after I sealed them. I researched this subject for a month after finding out you couldn't get the AR sealant or Roy's goo anymore. I even did testing on t shirt material. I think people that screw this up, use it straight out of the can or don't thin it down enough. I've been fortunate that my other models looked to have been resealed in the past and didn't need any attention except for sealing the speaker to the cabinet. The foam they installed had turned to dust.
 
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The actual maker of the sealant sold by vintage-ar is @RoyC, a
member both here and on Classic Speaker Pages, and it is still
available.

Permatex, silicone, and anything else with solids in them will
sooner or later ruin the pliability of the surround that has one
of those applied.
 
RxDx said:
The actual maker of the sealant sold by vintage-ar is @RoyC, a
member both here and on Classic Speaker Pages, and it is still
available.

Permatex, silicone, and anything else with solids in them will
sooner or later ruin the pliability of the surround that has one
of those applied.
Click to expand...
That's nice to know that he still sales it. I read on one thread (can't remember cause I've read many) that he doesn't. If it eventually goes hard and out of compliance I'll simply replace them. But so far no problems. There's tons out there for $15 to $20 bucks each. But like I stated in my last post I've only needed to dope the 24. The others only had a small amount of pin holes so I didn't mess with them.
 
I've used 3M Scotchkote as a sealer on KLH woofers. It's not viscous, maintains its resiliency and does not stiffen over time. And if you want to thin it even further, use toluene.unknown.jpg
 
That product appears to be similar to the “liquid” electrical tape sold in hardware stores, which is rather viscous and forms a membrane. It’s not ideal for the woofer’s Fs.
It is often overlooked that the original sealant is still present on the surround. Care must be taken not to add anything that will compromise compliance, and change the intended response.

Vintage_AR’s eBay store is permanently closed due to his recent passing. I will continue to provide sealant to forum members on request until it is gone. Just send me a PM…

Roy
 
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We measured many materials like this. If it “dries”, regardless of its flexible nature, it can be an issue. A subjective impression is not a substitute for measurements.
…but as long as you like it, that is all that matters.
 
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This to whoever has taken over Vintage AR sealant. Did Roy C have any connection with Alex Barsotti? Alex was the AR repair guy, having worked there for many years. I have a little of your sealant left, but it has dried up. What is the solvent? And if you don't plan to continue the business after your supply runs out, I'd be happy to do it to continue to make it available. You just need to give me the recipe at the appropriate time. Andy Kotsatos
 
Roy here…

I developed the sealant, and still have enough available for forum members and word of mouth referrals. “Vintage AR” was Larry Lagace. Since I was already doing much of his technical work, I would bring it to his shop as needed. It was also available through a local audio repair business (Stereo Workshop) here in the Albany area of NY, for which I worked. Unfortunately, both businesses are now closed.

Alex Barsotti, or “AB Tech”, became the sole oem AR parts supplier when AR went out of business in the early 90’s. ABT was the source for many of our oem parts, but never sold surround sealant. Larry purchased much of ABT’s remaining inventory when ABT went out of business, though by that time there were very few original parts left.

Eventually it became apparent that the sealant works best as a supplemental treatment for KLH woofers, which are known to have been insufficiently treated at the time of manufacture.

There are no current plans to advertise it for sale, though there have been recent inquiries to purchase the formula. It is very hazardous to make, consisting of a very large percentage of toluene…which, btw, can be used to reconstitute it. Unfortunately, toluene isn’t readily available in some states, and is becoming costly. Consequently, there are also labeling and shipping restrictions, and is the primary reason international shipping is no longer available.
 
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I would like to purchase some sealant if possible. Currently working on a set of KLH speakers I picked up by the curb yesterday.
 

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Roy, I can't find the "Conversation" feature, but I would like an amount suitable for 6 woofers. Walmart actually has toluene, also called toluol, for sale.

I have to annotate my post of Sep 25. The Model Nine was entirely the design of Arthur Janszen. I was a two design. We made the bass/mid freqency panels in house and bought Arthur's designed tweeters, the same ones that were in the Janszen electrostatic tweeters. There was one tweeter module per Model Nine panel.

Arthur subsequently designed a new tweeter array that was going to be used in the Model Twelve, but the tweeter was too inefficient to be used in a dynamic speaker, so the final Model Twelve used the same mids and tweeter as the Model Five along with a new woofer suitable for the larger enclosure. The Twelve is an outstanding speaker, but it didn't sell in big numbers. I think if it had been taller and less wide it would have sold better.
 
700K said:
Roy, I can't find the "Conversation" feature, but I would like an amount suitable for 6 woofers. Walmart actually has toluene, also called toluol, for sale.

I have to annotate my post of Sep 25. The Model Nine was entirely the design of Arthur Janszen. I was a two design. We made the bass/mid freqency panels in house and bought Arthur's designed tweeters, the same ones that were in the Janszen electrostatic tweeters. There was one tweeter module per Model Nine panel.

Arthur subsequently designed a new tweeter array that was going to be used in the Model Twelve, but the tweeter was too inefficient to be used in a dynamic speaker, so the final Model Twelve used the same mids and tweeter as the Model Five along with a new woofer suitable for the larger enclosure. The Twelve is an outstanding speaker, but it didn't sell in big numbers. I think if it had been taller and less wide it would have sold better.
Click to expand...
Andy,....hover over Roy's avatar and you will see a "start conversation" button.

If you happen to find some butyl rubber you can cut into small pieces and stuff into some cheese cloth and soak in a mason jar of toluene.
 
700K said:
BTW, if you have an ohm meter, I'd be curious what the DC resistance is of the Model 5 and Model 12 woofers. Likewise the person who had the two tweeters with the thin and thick top plates, I'd like to know the DCR of those 2 voice coils.
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@700K
Are you still looking for this information?
If so I can provide it.
Jef
 
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