Upgrading Klipschorn Woofers

[triceratops]

Maron,

I know it is time consuming to make technical explanations but I'm hoping you can go into more detail on the other alternate Khorn woofers besides JBL if you have knowledge of these. Thanks in advance.

>Regarding woofer upgrades you originally wrote:

There is alot of problems...The k33 is a cheapass looking woofer but it works beautifuly. Some people would like a cast basket, plus 4" voicecoil. But other perimeters are not met...I rember PWK using a special chemical (DPK) to lower resonance of cone. It took him about an hour on each woofer. I have only found 3 other woofers that would work beautifully in the Khorn and they are now not manufactured. One of which would cost (used) $1000. I have all three plus the K33. The three have better definition in the 200hz to 500hz area than the K33 but all are identical below 40 hz in the Khorn.

>Triceratops responded with this question:

What about the other bass drivers that were actually used by PWK in the Klipschorn of various generations?

1. EV 15WK

2. Jensen P15LL

3. Stephens Trusonic

4. University C15W (variable impedence)

Would any of these be an upgrade over the stock Eminence or CTS K33? I think at some point the EV was regarded as an upgrade by Klipsch and available as an exta-cost option.

>Your recent follow-up was:

...Cone kits are still available from JBL. The problem with the other types used in the Khorn EV, University, Stephens etc Is trying to get fresh cones/voicecoils if needed. JBL still has a vast inventory of parts for their speakers.

>In response I would ask:

Vintage speakers of the four types I mentioned are still widely available on the used market. Often purchasing one of these in good serviceable condition would not cost any more (and often less) than a new K-33 replacement. I realize that recone kits are typically not available for these speakers, but sometimes these vintage drivers have been in a horn-loaded cabinet isolated from the elements and still seem to be in excellent shape. If you're not looking specifically at parts or service, are there any of these speakers that could improve the sound of a Khorn? Any reason NOT to use these alternates in a vintage horn instead of a K33?

Thanks for any help you can provide.

Best in horns,

triceratops

[LarryC]

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On 3/14/2005 1:21:33 PM triceratops wrote:

1. EV 15WK

2. Jensen P15LL

3. Stephens Trusonic

4. University C15W (variable impedence)

...Vintage speakers of the four types I mentioned are still widely available on the used market. Often purchasing one of these in good serviceable condition would not cost any more (and often less) than a new K-33 replacement...If you're not looking specifically at parts or service, are there any of these speakers that could improve the sound of a Khorn? Any reason NOT to use these alternates in a vintage horn instead of a K33?

Best in horns,

triceratops

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Triceratops,

I managed to get a pair of 15WKs several months ago, tried one in my K-horn. It clearly had a higher output, much bolder bass, and good extended response well into the midrange. I had no SPL or other way to measure it, but, judging by the number of clicks on my preamp VC (!), it seemed to be at least 6db louder than the K-33E. However, that greater output and strong bass did not match up well with the rest of the K-horn, so I suspect some crossover engineering would be needed and I didn't keep them in. Thanks for your question, and I'm still curious about what Maron's three woofers are.

Larry

[ZAKO]

triceratops....the early speakers you have listed were modified to lower compliance of outer cone roll. the chemical used(DBP) DIBUTYLPHALATE was applied to modify free air resonce of cone. It had to be done properly so it would not leatch down into cone. A scientist from Monsanto George Ashworth worked with Paul Klipsch On proper application of this oily DBP. PWK & Ashworth spent alot of time on the problem of cone compliance. Your list of woofers were included in those they worked on. It was Stephens that later made a special woofer for PWK with the proper compliance suspension that would work in the Khorn based on the Stephens P-58-LX with a lower DC resistence. IT is this design perimeter that many of todays tweekers do not know about & are seeking a variant woofer. In just installing a stock EV 15Wk or standered Stephens or University C15W wonder why it does not perform as well as the various K-33 types. George Ashworth passed away. He passed on to me 155 technicle letters between PWK & himself on the design of the bass horn problem X-1, X-2, X-3 units. As well as the early mid horn development. These letters went into detail on the failures & sucesses in making these horns. The K33 is a good woofer for the Khorn. BUT it can be improved. Just a bit more. Ever so slightly other secrets will be revield. If I dont die first. A few close tweekers on this FORUM know some of it.

[Daddy Dee]

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On 3/14/2005 10:29:47 AM sfogg wrote:

"Having more detailed upper bass is an exciting possibility with Khorn."

Is that a function of the K33 or of the horn though?

The same K33 in a LaScala or Belle can get higher up because of the simpler horn.

Shawn

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Shawn,

That's what I'd been thinking, but thought someone posted above that they were hearing this with a particular driver in the Khorn.

[ZAKO]

Daddy Dee,,,Its a function of the Type of woofer in that horn

[bluesboy]

I used Altec 416-8A woofers in a set of K-Horns as well as a set LaScalas I've built and they sound great.

[triceratops]

>Larry Wrote:

I managed to get a pair of 15WKs several months ago, tried one in my K-horn. It clearly had a higher output, much bolder bass, and good extended response well into the midrange. I had no SPL or other way to measure it, but, judging by the number of clicks on my preamp VC (!), it seemed to be at least 6db louder than the K-33E. However, that greater output and strong bass did not match up well with the rest of the K-horn, so I suspect some crossover engineering would be needed and I didn't keep them in. Thanks for your question, and I'm still curious about what Maron's three woofers are.

>Larry,

Thanks for your input. I wonder if the EV 15WK needs a different size slot in the motorboard, or if there is some additional mod that the WK's go through when installed in a Khorn as per Maron's observations. I have a 1960 pair of Khorns that came stock with the EV woofer and a single 1961 Khorn that also has the EV woofer as stock. Something about the sound of these drivers appeals to me, but maybe the crossovers or motorboards are different on these Khorns to make it work.

>Maron wrote:

...the early speakers you have listed were modified to lower compliance of outer cone roll. the chemical used(DBP) DIBUTYLPHALATE was applied to modify free air resonce of cone. It had to be done properly so it would not leatch down into cone. A scientist from Monsanto George Ashworth worked with Paul Klipsch On proper application of this oily DBP. PWK & Ashworth spent alot of time on the problem of cone compliance. Your list of woofers were included in those they worked on. It was Stephens that later made a special woofer for PWK with the proper compliance suspension that would work in the Khorn based on the Stephens P-58-LX with a lower DC resistence. IT is this design parameter that many of todays tweekers do not know about and are seeking a variant woofer. In just installing a stock EV 15Wk or standard Stephens or University C15W wonder why it does not perform as well as the various K-33 types. George Ashworth passed away. He passed on to me 155 technical letters between PWK and himself on the design of the bass horn problem X-1, X-2, X-3 units. As well as the early mid horn development. These letters went into detail on the failures and successes in making these horns. The K33 is a good woofer for the Khorn. BUT it can be improved. Just a bit more. Ever so slightly other secrets will be revealed. If I don't die first. A few close tweekers on this FORUM know some of it.

>Maron, this is truly fascinating stuff, and I greatly appreciate your post. I have a University C15W that I pulled from a University Classic horn loaded cabinet and the outer cone roll is coated with a black tarry-looking material. I wonder if this is the same stuff you describe and if it was installed at the University factory or as an aftermarket tweak. I have not yet pulled my EV 15WKs from my Khorns to see if they have any visible treatment to the outer cone roll. I also once had a 1968 pair of Vertical Cornwalls (now owned by Audible Nectar) that had some sort of treatment applied on the outer cone roll, too. Could it have been factory installed?

In layman's terms, were the efforts to reduce cone compliance intended to reduce the excursions of the cone on low bass notes? Thanks for your insights.

Best in horns,

triceratops

Eugene, Oregon

[Daddy Dee]

Thanks Maron.

[LarryC]

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On 3/14/2005 3:55:48 PM Daddy Dee wrote:

Shawn,

That's what I'd been thinking, but thought someone posted above that they were hearing this with a particular driver in the Khorn.

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Dee, I left the wrong impression -- I heard that in free air. I suppose its range was not extended when installed in the bass horn, but it did have a very powerful, beautifully defined output from the deep bass up through the crossover limits. Unfortunately, it overmatched the squawker output and sounded unbalanced.

I had an EV 15WK in my solitary decorator model K-horn for a few years. I got a second decorator K-horn when I belatedly went stereo, around 1968, and became aware of a much weaker, less defined bass in the new one -- the 15WK bass and lower middle range was utterly blowing away that from the new one. To my great disappointment, I could not find another 15WK at that time. I guess K-horns improved overall after that, but it's a memory that doesn't go away.

Larry

[garymd]

I was around when Larry was testing the 15 WKs and indeed there was increased bass extension which was nice but he's correct in that major crossover changes would have been needed to make them usable in his khorns. There was also a fairly significant increase in the woofer's overall volume if I remember correctly. Not being a crossover expert and looking at the complexity of the AK-4s, it isn't something I would have attempted. Since his K33s sound pretty darn good to begin with, I would have done the same thing.......nothing.

[Tom Mobley]

Larry, don't forget I have a K-33 that belongs to you. It's currently in my DIY Belle.

[LarryC]

Thanks, no I didn't forget. Do you think you'll try it in one of your K-horns and play around more with those bass horn throat inserts at some point? How's your K's bass sounding now?

Larry

[ZAKO]

Larry...In responce to your question what three woofers would I use today as a dropin in my horn? The TAD 1601a, the 1601b, the 1601c. there is a Usher 15HM that looks interesting too. Also using the K33 modified. Using a mass ring installed in the voidecoil bobbin. or installed at the spider/cone area. gives lower bass extension. You have to determin how mutch weight is needed before attempting the mass ring modification, or going to a heavier cone. The EV unit higher output is a fooler playing a bit louder is not a lower bass extension. I wouldnt give you a dime more for that woofer if couldnt go a couple of Hz lower.

[LarryC]

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On 3/15/2005 9:05:20 AM Maron Horonzak wrote:

Larry...In responce to your question what three woofers would I use today as a dropin in my horn? The TAD 1601a, the 1601b, the 1601c. there is a Usher 15HM that looks interesting too. Also using the K33 modified. Using a mass ring installed in the voidecoil bobbin or installed at the spider/cone area. gives lower bass extension. You have to determin how much weight is needed before attempting the mass ring modification, or going to a heavier cone. The EV unit higher output is a fooler playing a bit louder is not a lower bass extension. I wouldnt give you a dime more for that woofer if couldnt go a couple of Hz lower.

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Thanks, Maron. Very interesting.

[garymd]

Sounded lower to me.

Actually, it was quite a while ago. Could have just been the volume but it DID sound lower!

[ZAKO]

garymd....Ive been fooled too. That why I play it once & measure twice. Overall the K33 aint a bad woofer. At $129 ea. Its a bargen. But if you got the big bucks You can mess with the big boys.

[LarryC]

The pyramidal wood inserts in the bass horn throats were yet to be removed (Search on "Restoring" for the thread) when I and Gary did the comparison, and those were still having the effect of greatly weakening the lowest octave from the bass horn. The 15WK powered right through that problem, which certainly made it sound like the bass was extended.

Maron, would the TAD 1601a be a drop-in? That's with the AK-4, probably a more complicated situation. I don't have the big bucks, incidentally.

Larry

[ZAKO]

laryc...I dont know mutch about the ak4. I use a electronic crossover and 6 mono block amps. I can adjust xover points, slopes, & levels. 2way 3way 4way. The TAD units sounded fine. But were no better than the JBL 2205 Just more expensive.