KLH woofers

[day67]

Hi, I'm new to the forum and the tech side of speakers. In bought my 1st stereo system in 1972, a pair of KLH 6's I still have -- and use. Just picked up a pair of 5's which lists (depending on where you look) the woofers as 11 or 12". Compared them to my 6's and waddeya know, Same speaker size! I measured these things 6 different ways and they are the same physically. Ironically, the grill cut outs for the woofer in the 6's are larger than the cut outs on the 5's!! Disappointing -- the 6's sound better too, but I'll wait to see once I have the 5's crossovers recapped. Question is, "is there ANY difference in these 2 models' woofers, sonically or internally??"

[Guest matty g]

Hi Model Five owner

You are very lucky indeed - Model Fives are not very common. I'm surprised they don't sound a little better that the Sixes, particularly in the midrange. I really like the Model Six, but find the midrange a tad bit shrill and always thought a three way set up would cure that.

Anyway, as far as I know they are the same woofer although the crossover is different and possibly the low bandpass coil. Chances are that the two midrange drivers are wired in series, which means if one voice coil goes, both drivers go dead. You probably have already checked that out, but I just thought I'd mention it. Can't imagine why the grill cutout would be larger, but it's one of those not quite 11" odd size woofers of the diameter used in the AR2 and other New England systems. Nice find!

Matt

[Andy]

The Model six and Model five do NOT have the same woofers. If you pull them out of the cabinet, you'll see that the Model Five has a noticely larger magnet. Also, Model Five's have a number written on the front of the cone, this is the cones weight in grams (should be about 25 grams.) A complete model six woofer weighs about 5 lbs. and the Model Five Woofer weighs about 8 lbs. The only way they would be the same size is if someone replaced the Five's woofer with one from a Six ?

Also, the Model Twenty Three Woofer is the same as the Model Five.

[day67]

Interesting!! Aaaahah! I havent had the woofers out yet but it I'm willing to bet someone stuck in a pair of 6 woofers as bolt pattern and frame diameter are the same and from the outside cant tell the difference.. . Thanks, of all the info I have sought, this has been most helpful.....And I agree, the 5's SHOULD sound better than the 6's .. you would think. This is a great forum!

[Guest matty g]

Thanks Andy!

Sorry about the mixup - I've never taken apart and closely studied the two systems, only seen and heard them side by side many, many years ago. I do remember the Five being less shrill and more defined, as I thought they should. I thought the only difference was the mid setup - glad you're on the ball! And I agree with day67 - this is a GREAT forum!

Matt

[Andy]

Yes, this forum is a great thing, I've enijoyed it for over 5 years. whether it's tech help, history or just a good old fashioned loudspeaker story, The classic Speaker Pages is he place to go !

One further difference you should notice about the Model Five compared to the Six is the Five's improved bottom end....just a bit more solid bass resonse due to the larger woofer and slightly larger cabinet.

[Guest Feighner]

The cone size of the six woofer is the same as a normal 12 inch. it fits in a 12.75 cabinet because it didn't have a basket like conventional woofers.(the magnet was attached to the front panel by tubing and epoxy and the cone is glued to the panel) So the hole size is different than expected.

[Andy]

Freighner is refering to pre 1965 Model Six woofers, epoxied type in which a repair will be difficult. The 1965-72 Woofers are standard screw in basket containing the entire woofer.

[day67]

Hey, what I think I found out is this: The early KLH 5 woofers were of the round magnet style. Then -- maybe around the time they changed the crossover from the early style to the printed board, the square magnet came to be, 1970 or so. Does this mean anything as far as the way the crossover is set up or the frequency perameters?

[Andy]

Dan, That could very well be. Recently there were some model 12 woofers on ebay which had a very tall round magnet, not at all like the model 5 or 23. Until I saw these, I thought model 12 woofers were the same as models 5 and 23. Looks like there might have been more changes to speakers mid production run then I thought.

KLH did improve the electronics and make upgrades on it's modular systems, Models 20,24,26 etc. by upgrading transistors. One would have to check schematic changes for given speakers and components. Some schematics are labeled "revised" along with a date.

A couple of years ago I logged serial numbers along with production changes to every KLH Model 8 radio I saw for sale by emailing sellers for details, most were on ebay. This project took close to two years and I ended up with details on over 150 examples. I learned a lot about these great little radios in that time.

Im sure speaker details could be pinned down to the date of change, but one would have to start logging serial numbers and details.....something to do on those long winter days!

[soundminded]

The KLH model 5 woofer is superior to the KLH model 6's having greater power handling ability and I think responding to lower frequencies. It adds a pair of their excellent 5" full range drivers for use as midrange speakers and uses the same tweeter. the cabinet is larger and heavier. It's also styled differently. I measured the working part of the cone, the paper on Model 6 and it has almost the same diameter as AR2a. KLH advertised Model 6 as 12", AR advertised Model 2a as 10". On paper Model 5 is a better speaker than Model 6. It originally cost about 50% more and they were available at the same time. I haven't heard model 5 in a very long time but as I recall, I preferred model 6 as having better balanced clearer sound. That was in the era before equalizers. Carefully equalized, I think and expect my opinion would change. Interestingly, if you look at the schematic for model 5 on this site, you will see that the midrange control actually controls the tweeter frequency countour, not the level of the midrange drivers.

[dynaco_dan]

>Dan, That could very well be. Recently there were some model

>12 woofers on ebay which had a very tall round magnet, not at

>all like the model 5 or 23. Until I saw these, I thought model

>12 woofers were the same as models 5 and 23. Looks like there

>might have been more changes to speakers mid production run

>then I thought.

>

Hi Andy;

Those unusual woofers should be here any day now.

I saved the photos from that auction as well.

I'll see if the seller may have copied down their serial numbers off of the cabinets.

I also picked up the KLH Twelve/Five mids for spares.

The mids were also considered their single fullrange driver for smaller systems.

Readers note that the mids are open backed so that they always need a sub enclosure or they will be destroyed by the woofers back pressure.

They may also work as a woofer drone for a second or two. lol

[dynaco_dan]

Hi again;

Just a profile of the mids for a better view.

[dynaco_dan]

Hi again;

This is a later KLH Five square woofer magnet and a crossover.

From what I've read, this same woofer would only be inter-changeable with KLH Twelves, round or square magnets, and KLH Twenty-Three's, but not KLH Six or other same diameter woofers.

[Guest matty g]

Nice pics Vern - those woofer magnets are massive. The midrange drivers look familiar....did they use those in the Model Twenty One table radio?

Matt

[dynaco_dan]

>Nice pics Vern - those woofer magnets are massive. The

>midrange drivers look familiar....did they use those in the

>Model Twenty One table radio?

>Matt

Hi Matt;

One woofer and the two mids arrived here yesterday, that is another story.

The woofer is really nice in construction.

I will comment about the KLH fullrange/mid range drivers now.

They have the open back steel stamped frames.

They appear to be used in single speaker applications, at least one dual driver model and as mids for the KLH Fives and KLH Twelves.

I honestly do not know if these also came in different impedances or with closed backs.

Or maybe there was only the one model ever produced for it's life.

Perhaps another reader may correct me on this detail, please.

As is, with the open backs, they would need a sub enclosure if used with any woofer in the same speaker system.

As I see it, their use in radios, portables, etc would need no special sub-enclosure, as it's own enclosure would enhance the limited bass.

The added cost for the Fives and Twelves of the extra sub-enclosures was probably offset by manufacturing only the one model, we shall see about this comment.

As the world turns, we shall see what comes from other readers.

Here is that missing regular KLH woofer photos that went to neverneverland.

[dynaco_dan]

>>Nice pics Vern - those woofer magnets are massive. The

>>midrange drivers look familiar....did they use those in

>the

Model Twenty One table radio?

If I didn't answer this question it is because I do not know that answer with any honesty, at this time.

>One woofer and the two mids arrived here yesterday, that is

>another story.

>

>The woofer is really nice in construction.

>

Hi again;

Monday the first woofer arrived and the second arrived today.

I have not done anything but test them and they are ok.

My guess is they weigh about 9 - 10 pounds each and the round magnet is another guess at about 5" in diameter.

In the profile photo the top magnet chrome plate edge to the bottom chrome plate edge is about 2" overall thickness.

Cone material is very heavy weight with a reverse roll cloth surround, which is identical in appearance to the Larger Advent woofer surround as opposed to the AR outer roll surround.

The date rubber stamped on the rear of the magnet of one woofer only is Jan 12, 1968, the other is smeared but I can check it again later if anyone is interested.

If anyone here is an data archivist with historical interests please post your driver questions here.

I have requested, if available, the serial numbers of both KLH Twelve cabinets from the seller.

I was thinking about these woofers with the reverse roll which is the same as other KLH woofers and mid/fullrange drivers.

By having the roll reversed the cone can travel forward without the surround touching the grille cloth allowing a shallower depth of cabinet face by maybe 1/2".

This would then have less of a surface for reflective interference, maybe.

Story time:

Another thought is when the very first woofers were about to be setup with their surrounds at the KLH factory, an apprentice, like myself, went around the work benches with all the woofer baskets looking up.

This apprentice, me, had an armful of only the surrounds on one arm.

Holding onto them and the other placing the surrounds on each woofer frame ready to cement them.

They fit upside down into the cone/frame gap, and would not fall off onto the floor.

I would have then forgotten what I was told and would have gone around and just glued all the surrounds to the frames and cones, upside down.

Henry Kloss arrives in the morning and see's my goof, he thinks about it, and decides that I may have something there, I am a genius, and I get a raise.

End of story time: lol

The mids arrived on Monday, sadly one was destroyed in transit.

Anyone who sells and ships speaker drivers should be extra cautious in nutting and bolting drivers together face to face, with suitable spacers on application.

Not using softer materials, such as, but not limited to, thread, string, garbage bag wire ties, small guage copper wire, nylon zap straps, and particularly copper coloured electric motor winding wire which has been coated to appear to be copper for decades, but is in fact soft aluminum wire which breaks easily on a knick.

I've received most every one of the above bindings and then some.

Zap straps work great for tyeing together an electrical cable to a pipe, or just to tye cables together, etc.

Two Larger Advent woofers with 4 zap straps made the journey here via USPS surface but the weight and forces received in transit sheared all 4 of the zap straps, so much for my earlier ebay suggestion to sellers.

One can only imagine the shipping of 2 AR 12" woofers, earliest or later style.

If anyone would like to ship me 2 AR 12" woofers I sure would appreciate the thought and I will write a write-up upon their arrival on their condition.

This would be a good firsthand test case.

They of course would be free. lol lol

Frank, Frank?

[Guest matty g]

Hey Vern -

I meant to ask you - what are you doing with the mids and woofers, anyway? Do you have a set of Model Twelves that you are restoring? If so, would you mind posting a pic or two? I'd like to read about any project or research you are doing if you have the time to write about it. Those drivers were a great find.

Thanks

Matt

[dynaco_dan]

>Hey Vern -

> I meant to ask you - what are you doing with the mids and

>woofers, anyway? Do you have a set of Model Twelves that you

>are restoring? If so, would you mind posting a pic or two? I'd

>like to read about any project or research you are doing if

>you have the time to write about it. Those drivers were a

>great find.

>

>Thanks

>Matt

Hi Matt;

I do own a pair of A-50's, ugly black painted cabinets, hideously dirty grille cloths, but they still sound nice to me.

I picked them up at a second hand store, after seeing the ugly, and I mean ugly boxes on the dirty floor, I only spotted the logos or I would have not touched them, only $100.00 the pair, at least they were working properly.

I may one day, or not, strip the paint and hopefully there is a reasonably good walnut veneer remaining underneath to re-finish.

My health does give me the ability to do what I would like to do or for very long.

The cloth cannot be brought back from the dead, it is so bad.

These are 2 spare woofers for my Twelves, that I didn't need to buy.

The 2 mids, one was destroyed in transit, are for spares also.

I have been buying spare drivers for various speakers for a while now.

I have been much more successful receiving usable KLH mids, than I have been at buying AR dual tweeters, which I've lost, due to being just dead or being damaged in transit, more than 90% plus of those I have bought.

I am trying to get communication going with the seller now regarding the destroyed mid driver but I am very pleased with the woofers.

Goodness, they were well made and heavy, real heavy, thank you Henry Kloss.

They were a good buy, $9.00 and $13.00 each plus exchange and S&H of course.

I am expecting a package any time now with my last 4 mids from a later auction.

I worked at the local warantee depot here, Dynaco, AR, etc the owner and I have remained friends all these 35+ years.

We have dinners every month or so, he was a very capable and honest service tech, and a nice man to boot.

He was not a hifi buff and never kept any old documents that we would find of value reading here today.

When James, the draftingmonkey, and his charming wife, Linda were here at Christmas time, I would loved to have arranged an evening with my friend, my big bros, and our fellow member's from Canada, poor Linda though, hifi boredom.

Perhaps at another time, members can have a gathering somewhere to exchange hifi stories, firsthand.

[Guest matty g]

Vern -

Sorry to hear about the mids damaged in shipping. I do the same thing - any time I find AR mids and tweeters I buy them. Also KLH drivers (usually the ones for Seventeens, Sixes and Twenties). Never bought any off of ebay, though. I'd like to hear a pair of A-50's someday - another great find.

It's getting crowded in here - I've got AR3a's, AR2a's AR5's, 3 pair of 4X's, TSW 610's, a pair of KLH Sixes, KLH Twenties, Fisher XP7's, and of course the great Dynaco A-25's. And those are just the speakers! The 3a's and the A-25's are my daily drivers. The 610's are with the big basement system - you've got to have choices, you know. I'm restoring the 5's right now.

I guess you could say I'm officially an audio FREAK. One thing I must say, however, is that this hobby attracts the nicest people.

Take Care

Matt

[dynaco_dan]

>I do own a pair of A-50's, ugly black painted cabinets,

>hideously dirty grille cloths, but they still sound nice to

>me.

>

>I picked them up at a second hand store, after seeing the

>ugly, and I mean ugly boxes on the dirty floor, I only spotted

>the logos or I would have not touched them, only $100.00 the

>pair, at least they were working properly.

>

>I may one day, or not, strip the paint and hopefully there is

>a reasonably good walnut veneer remaining underneath to

>re-finish.

>

>My health does give me the ability to do what I would like to

>do or for very long.

>

>The cloth cannot be brought back from the dead, it is so bad.

>

>These are 2 spare woofers for my Twelves, that I didn't need

>to buy.

>

>The 2 mids, one was destroyed in transit, are for spares

>also.

>

>I have been buying spare drivers for various speakers for a

>while now.

Hi again;

I'm going brain dead now.

I wrote about the Dynaco A-50 speaker system I bought and this is the KLH Twelve woofer topic. duh!

I came across the KLH Twelves in another secondhand store/pawn shop when I reached over top of an ugly floorstanding speaker to read the information off of the rear of an electronic crossover sitting on top.

I looked down and this crossover console was Velcroed to the the top edge of the cabinet facing up to me.

If that box had been stuck on sideways or upside down or on the rear floor I would have missed buying another pair of speakers I didn't need.

KLH Twelve printing on the front of it excited me to no end, I had only read that this speaker and the AR-3A were the 2 best speakers available in Consumer's Guide that issue so many years ago.

I am certain I moaned out loud in delight.

Until this first contact I never saw or thought about how large these babies were.

These were also about $100.00 CDN for the pair.

They weigh about 80 - 100 pounds each.

These are floorstanding and definitely too big for a shelf or stand.

Cabinets are roughly 24" wide, 30" high and 18" deep with the external remote control crossover attaches with a 4 wire unbilical cord.

The wood is oiled walnut and the cloth is an ugly, to me, cream coloured very course looking grille cloth.

The cloth may have been very sonicly neutral and appearance came second.

I have had no reason to open up either cabinet to have a looksee.

I have seen a few KLH Twelves for sale on ebay minus the crossovers.

I believe a member was trying to use a pair without the crossovers, an accident waiting to happen, when there is no coils or caps for the mids and tweeters.

I have also seen a few crossovers by themselves for sale on ebay.

They are a discussion in themselves.

Two really great members helped me out with a few pieces of KLH information sheets, thank you fellas.

Sadly, I feel these being so large and only floorstanding, they probably lost out to much smaller bookshelf speaker systems.

[dynaco_dan]

Hi again;

Just when I thought I was now fully aware of which woofers were for which speakers system something comes along and spoils that allusion.

Here is 3 woofers from 2 KLH Five's and a KLH Twelve;

In 1 and 2 is a KLH Five woofer, note the single dark round magnet, different from 3 and 4.

In 3 and 4 is my KLH Twelve woofer I just bought from a KLH Twelve auction, note the two separate dark round magnets.

In 5 and 6 is a later style KLH Five with the square magnet woofer.

If this doesn't confuse the ability for us to know which 10" woofer is for which speaker system.

Before I bid on that auction for the KLH Twelve woofers and mids I read here that the KLH Twelve, Five and Twentythree use the same woofers.

I do not know enough regarding the KLH classics to confirm this or not.

I was satisfied enough to bid for and buy them.

What I feel I need now is more knowledge on the KLH 10" classic woofer line.

The KLH Six also used the same size 10" woofer, how will we be better able to diferentiate between the various 10 inchers by size listed alone.

Such as those listed for sale and a model number was not available or multiple model uses are claimed by a seller.

[Guest matty g]

Vern

Maybe if the auction pictures show the cones, the weight written on the cone will be visible. Are the weight numbers different on the various cones that you have?

Matt

[dynaco_dan]

Hi Matt;

I have the KLH Twelve woofers with the two dark magnet sections, the other photos are off ebay.

The one woofer that I just looked at here, has no markings on the rear of the cone but has 26.3 black felt marked by hand on the front of the cone.

Looking at the other one, again there is nothing marked on the cone rear but there is a 12 and 25 hand felt marked but by different persons and different felt markers on the cone front.

These were from ebay KLH Twelve speakers.

[dynaco_dan]

Hi again;

Here is three KLH Twentythree photos.

This was earlier mentioned as being the same woofer as also used in KLH Five and KLH Twelves.

Note that the cones are hand black felt marked with numerals.

Not matching numerals either 26.1 and 23.2.