chronology - development/appearance of PWK's classic exponential horns ?

[karlson3]

aesthetically, I find PWK's metal exponential horns quite beautiful and their performance vs bulk & size very good vs other flare horn and waveguide.   What was the first metal horn designed by PWK? Did PWK do all the development work of them alone?  - Who (if known) did the artwork of putting his logo into the molds?  What years did they (K400, 500, 600, 700 and others) first appear?  

[WMcD]

You should read his article.

 

 

[karlson3]

Thank you very much. The slow expansion and long neck of K400 provided acoustic EQ at higher frequencies.  I wonder if one of the unnamed horns was the Altec 511? (it was shown in PWK's comparison of 447 - La Scala to Altec's VOT)  Was a version of that paper published in "Dope From Hope" to introduce K400 to the public ?   I have K400 (in my Khorns) K700 in and out of my Heresy I, K-260 and 1 - K600.   How large of a baffle should K600 have for proper support when using it on top of a LF unit?

[WMcD]

I don't know about unnamed horns or Altec.  

 

I believe that any EQ is mostly from the interaction of the rectangular mouth and the flair in the horizontal.  At high freqs the horn starts beaming in the vertical.  This is PWK's controlled directivity.

 

You can look at the many DfH.  There is no extensive discussion of the K-400 to my knowledge.  He made the article available in "The Klipsch Papers."

 

As far as size of baffle. Mechanically, the I don't see a mechanical problem with plywood and screws.

 

Acoustically, we have an issue of just how large it must be to improve the impedance at the mouth. In a CW we have a lot of real estate.  LaScalas and decorator K-Horns may be a guide.  The baffle board is not really too big compared to the mouth.  Maybe just doubling the effective area of the mouth.  I'll suggest  9 inches high and 14 inches wide if you have a space issue.

 

WMcD

 

 

[boom3]

The flare of the Heritage horns is dictated by the exponential expansion. I once saw PWK draw an exponential curve freehand. I bet that was very, very close to the ideal curve. Bill is right about the baffle size. I'd also add that Paul's paper, "A High Quality Loudspeaker of Small Dimensions",  (Journal of the Acoustic Society of America, Vol.17, January 1946) which discusses the development of the K-5-J, would be of interest. That and the K-400 paper show his evolution in thinking up to 1963.

 

I have always felt that the large baffle of the Cornwall is the main reason why the midrange integration between the woofer and midrange is so good.

 

The K-600/601 horns are pretty good, but if you have the real estate on your baffle for the K-401, and the depth to accommodate it, I'd go for it.

Having said that, horn design has marched on and there are better horns than the K-401 out there for midrange use. They've been discussed in great detail in the forum.

[WMcD]

Don't call me Bill.

 

In my view, the K-5 was a big breakthrough and remains a classic.  It resembles the later Manta Ray.  

 

It is my understanding that the the throat end had a metal casting which must have been expensive to sub out.  And I believe there was a variation to take a larger driver.   The bell end was made of fiberglass  and ply and was a bear to fabricate.  IIrC there was a photo in the biography showing a jig with a hot plate underneath to force curing.

 

Cost of manufacturing was a concern.  The K-400 had fewer complications and in some ways better performance.

 

From 13 years ago:

 

 

 

It was 

[WMcD]

In this thread I've posted a picture of a cast (maybe not the only) for the K-400

 

 

 

[boom3]

"Don't call me Bill"

Sorry...William?

[WMcD]

William is good.  Thanks for understanding  

[LarryC]

And here I thought it was "Gil". 

 

- Larry

[JRH]

Paul's first metal horn was the K-1000 used in the Rebels, Shorthorns, and early Heresy's and Cornwalls.  This would have been 1950 +/- a year.  We have his wooden pattern on display.  Paul liked to get his hands dirty, and did virtually all of the pattern making and first-off moldings himself.  In the case of the K-400, he first built one from sheet metal and covered it with "tar".  It is also on display.  I believe it was the K-700 that was plagiarized from one he pulled out of John Eargle's trash can when he worked at Jensen.  Otherwise it was all him thru the K-260.