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Speakerlab K Horn [message #19016] Sat, 16 December 2006 11:38 Go to next message
Paul C. is currently offline  Paul C.
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Registered: May 2009
Master
I was digging around in my "archives" (junk on my bookshelves) looking for some Speakerlab K Horn info for another fellow and dug this up. I have often heard it stated that the Speakerlab K was misdesigned, the throat was wrong. Apparently that was on purpose:

(From Speakerlab's Technical Compendium TC-10 1979, by Pat Snyder)

"A Shortcut (pun intended)

"You will find that bass horns designed strictly to the forumula are quite long. Olson demonstrated (Reference 1, p. 114) that the horn can be shortened considerably, with little adverse effect on the bass response, by using a faster taper rate in the throat end. In addition this extends the high frequency range of the horn.

"The Speakerlab K uses a 100 hz taper rate for the first 8 inches of horn path from the throat, then a 48 hz taper rate thereafter. A line for the SK is plotted on figure 5.


"References

"1. H. F. Olson, Elements of Acoustical Engineering, 2nd Ed., Van Nostrand, New York, 1947. Out of print."

Re: Speakerlab K Horn [message #19017 is a reply to message #19016] Sun, 17 December 2006 09:57 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)

This was described as a "rubber throat" in a paper written by Paul Klipsch in 1941 called "A low frequency horn of small dimensions". He proposes that his Klipschorn corner horn have an initial wide taper for the first eight inches corresponding to a 100Hz flare rate. The rest of the passages have a slower flare, corresponding to a 47Hz flare rate.


Re: Speakerlab K Horn [message #19033 is a reply to message #19016] Thu, 28 December 2006 18:13 Go to previous messageGo to next message
DMoore is currently offline  DMoore
Messages: 58
Registered: May 2009
Location: Seattle
Baron
I have the original 1979 Speakerlab "K" plans, and that is definitely NOT a 100Hz flare rate at the throat. I also haven't ever seen this article that you reference.

The plans show the same 50Hz flare rate used by the original Klipschorn. Also the remaining "K" flares are 32 and 38Hz respectively with the same overall horn pathway length (approx. 64 linear inches). Both horns employ a 78 sq. in. throat area cross-section. A virtual Khorn knowckoff with a couple of improvements, funny since they were originally included in the 1946 Klipsch plans (a 12" driver size) but were subsequently dropped by Klipsch production some time later. These include back chamber "stuffing" and back chamber/channel axially aligned bracing to reduce vibration.

Most likely, the THROAT CAVITY OPENING of the Speakerlab "K" is the so-called "wrong" part, evidently copied directly from a post-1962 Klipschorn, being that it is 3" wide versus the 6" wide typically used for a non-K33 driver, such as the W1508S 8 Ohm driver used by Speakerlab. This is where the SL "K" MAY have been improved BUT I heard a pair of "K"s at the time, and in no way do I think that they suffered in the least from using the smaller slot size. I've NEVER heard a Klipschorn that beat them on the bass-end to this day.

DM



Re: Speakerlab K Horn [message #19034 is a reply to message #19033] Fri, 29 December 2006 00:36 Go to previous messageGo to next message
Paul C. is currently offline  Paul C.
Messages: 218
Registered: May 2009
Master
"I have the original 1979 Speakerlab "K" plans, and that is definitely NOT a 100Hz flare rate at the throat. I also haven't ever seen this article that you reference."


As I said, this is from a Tech paper from Speakerlab.

From Speakerlab's Technical Compendium TC-10 1979, by Pat Snyder

This paper, as well as about a half inch thickness of other technical papers, were what Speakerlab sent out as their "Speaker Design Book". Most were written by Pat Snyder, one of their engineers, and were papers presented at AES meetings.

If you wish, email me. I'll try to scan it, but it is printed on green paper. I'll see if I can lighten it up enough to read. I quoted Mr. Snyder accurately.



Re: Speakerlab K Horn [message #19037 is a reply to message #19034] Fri, 05 January 2007 17:35 Go to previous messageGo to next message
DMoore is currently offline  DMoore
Messages: 58
Registered: May 2009
Location: Seattle
Baron
Well, Speakerlab was wrong. Not you. Just don't believe everything that they publish!

Clearly the 100Hz reference is a direct and mistaken ripoff from the original 1945 Klipschorn patent document, which was concerned with a smaller version featuring a single 12" field coil driver which DID indeed use a 100Hz flare rate at the throat. So much for copying the at-the-time-and-still-current-flavor of the larger 15" driver version of the Klipschorn and not knowing why it's the way it is...

However, the 1970's Speakerlab "K" used the familiar 15" driver and the normal 50Hz throat expansion rate, as indicated in the Speakerlab "K" plans. Anyone with a ruler can figure it out. Wavelength/18.1 = exponential area doubling length, and that isn't going to amount to 100Hz (that would double its area every 8 inches (approx) of linear travel)!

The throat area cross-section doubles, according to the plans, at at approx. 16 inches, measured center of channel, which would be 50 Hz, thereabouts.

DM


Re: Speakerlab K Horn [message #19038 is a reply to message #19017] Fri, 05 January 2007 18:37 Go to previous messageGo to next message
DMoore is currently offline  DMoore
Messages: 58
Registered: May 2009
Location: Seattle
Baron
This again refers to the early 12" field coil version as in the 1945 patent which is quite a bit different than the larger 15" version which the Speakerlab "K" was cloned from.

Gives me the willies that Speakerlab was so blatently uninformed about what they were doing! Blindly copying.

But at least its not a bad copy, anyway. Couple of improvements, to boot!

DM

Klipsch KPT-MCM-4-T Grand [message #19058 is a reply to message #19038] Wed, 31 January 2007 18:21 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)

I get the feeling you're a Klipsch fan. How do you think the Klipsch cornerhorn sounds compared to their more modern top-of-the-line horns, like the KPT-MCM-4-T Grand with its dual-15" basshorn, it's 12" tractrix mid and its 2" tractrix tweeter horn?

Re: Klipsch KPT-MCM-4-T Grand [message #19061 is a reply to message #19058] Thu, 01 February 2007 18:20 Go to previous messageGo to next message
DMoore is currently offline  DMoore
Messages: 58
Registered: May 2009
Location: Seattle
Baron
Well, I guess I'm a fan of Paul Klipsch the horn designer and business man rather than just a fan of his products alone. My personal taste is more "corner-centric" as far a horns go...

I imagine the scale and power of the MCM stack would be impressive (and I don't just mean the footprint), to say the least, but I haven't heard them. But I have studied the available documentation about them, though.

Stacked in a pair, the throat size is correct for the "official" 30Hz in 1/2 space according to the Gillum patent document if I remember correctly. I would expect to be impressed, at any rate.

I have played around with a 2" tractrix midrange horn (DIY), and they have a distinctive "flavor", quite addicting actually. It has to do with the way that the sound propogates, rather than having a particular "sound" in its response. It's rather like when a nice speaker system broadcasts into a large, quiet, non-reflecting space. Except it's in your room. A positive effect, to say the least.

DM

Re: Klipsch KPT-MCM-4-T Grand [message #19062 is a reply to message #19061] Thu, 01 February 2007 18:33 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)

Paul Klipsch has always been one of my favorite speaker designers too.

I'd like to see that MGM, as I don't know anything about it except what I see in the picture. The midhorn and tweeter are pretty easy to see, but you can't know what configuration the basshorn uses from the picture. It looks like a W-bin, but I can't know for sure.


Re: Klipsch KPT-MCM-4-T Grand [message #19064 is a reply to message #19062] Thu, 01 February 2007 19:07 Go to previous messageGo to previous message
DMoore is currently offline  DMoore
Messages: 58
Registered: May 2009
Location: Seattle
Baron
Do you want the patent document? I can email it to you. Or if you have a place to put it to make it available here, we can set a link, etc.

Tell me where - and it's there!

DM

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