KLH Twelve woofers

[dynaco_dan]

Hi there;

Does any of the members know which woofers, from which other model KLH speakers, are the same as the KLH Twelve's 10" woofer.

I am guessing just the KLH Five's, but I may be wrong.

Has anyone seen a schematic of the KLH Twelve speaker system and crossover network?

Thank you.

[Andy]

Yes, the model Five woofer is the same as the model Twelve's. Also , the woofer in the model Twenty three is the same. Many model 5 & 23 woofers have the weight of the cone in grams written on the cone, usually around 23-25 grams. The model 6 cone weighed in at about 18-20 grams. The models 5,23 & 12 had the big square magnet, giving the speaker a total weight about 8 pounds. The model 6 weighed about 5 1/2 LBS. having a round magnet. The Woofer in the models 17, 20 and 33 was lighter still with a small square magnet.

[dynaco_dan]

Hi Andy;

Thank you very much for the information.

[tysontom]

>Yes, the model Five woofer is the same as the model Twelve's.

>Also , the woofer in the model Twenty three is the same. Many

>model 5 & 23 woofers have the weight of the cone in grams

>written on the cone, usually around 23-25 grams. The model 6

>cone weighed in at about 18-20 grams. The models 5,23 & 12

>had the big square magnet, giving the speaker a total weight

>about 8 pounds. The model 6 weighed about 5 1/2 LBS. having a

>round magnet. The Woofer in the models 17, 20 and 33 was

>lighter still with a small square magnet.

Andy, this is good information. Do you know the details of the voice coils; e.g., the diameter of the Model Five and Model Six voice coils, and the overhang? You would have to had dissassembled some of them unless you have any original drawings. I know that early Sixes had something like a 1-3/8-inch diameter voice coil, much like the AR-2, but I don't know about the Five, which was heavier.

--Tom Tyson

[Andy]

I have no details on the voice coils of these models having never taken any of them apart.

I stand corrected on the model Twelve woofer; see ebay number 170063625000. It has a large round magnet (not square) which looks the the one used in the model six, but is no doubt larger since the model Twelve was the top of the line offering by KLH in the late 60's.

Note: this seller is parting out two model Twelves for those looking for parts ?

[tysontom]

>I have no details on the voice coils of these models having

>never taken any of them apart.

>

>I stand corrected on the model Twelve woofer; see ebay number

>170063625000. It has a large round magnet (not square) which

>looks the the one used in the model six, but is no doubt

>larger since the model Twelve was the top of the line offering

>by KLH in the late 60's.

>

>Note: this seller is parting out two model Twelves for those

>looking for parts ?

Andy, I had always heard that the KLH Five and KLH Twelve shared basically the same woofer, but that may not be exactly right. The enclosure volume in the twelve is much larger than in the Five, and the magnet structure would surely have to be different to address the different characteristics. Ironically, a larger enclosure usually denotes a *smaller* magnet -- all things equal -- for appropriate damping, but I think KLH designed significant contouring in the Twelve crossover, but I'm not sure what was done on the low-frequency end. It is very difficult to significantly change anything (read "equalize") down in the very low frequencies with a passive crossover, so I suspect that damping was worked on in that speaker. That Twelve woofer on eBay shows stacked magnets for additional motor strength. Since the cabinet is much larger than the Five, the woofer may have utilized a stiffer mechanical suspension to offset the reduced acoustic restoring force, all the while retaining a long overhang in the voice coil. This would call for additional magnetic strength.

--Tom Tyson

[dynaco_dan]

Hi Andy;

Thank you for the heads up on the KLH Twelve woofer auction.

True original replacement KLH Twelve parts are not all that common today.

I have seen one or two separate panels for sale in the past, but 2 looked liked a truck ran over them and another didn't work.

A few auctions for the complete KLH Twelve speaker system have bombed out because of very high shipping costs, they are heavy beasts.

I believe it was writtem here previously that someone was attempting to run a pair of KLH Twelves without the crossover network.

That person was trying out different connections without knowing which was correct.

I do hope that none of those tweeters or mids were damaged.

The mids are a very versatile driver, they were used in various full-range applications, as well as the KLH Five and possibly other mid range only applications.

Having open backed frames, means the mids cannot be just used with just any enclosure.

They cannot be used with a woofer unless they are installed with it's own sealed sub-enclosure, or they would act as a passive radiator for a few seconds maybe.