garyrc Posted January 9, 2018 Share Posted January 9, 2018 I've heard that, when AR (acoustic research) got good reviews of their early acoustic suspension speakers (AR-1? AR 3A?) that PWK ran curves on them, and they were not as flat as they were cracked up to be. Do you have these? Can you share them with us? A 1977 brochure describing the Klipschorn read, "...And we test every speaker that makes a serious claim to quality reproduction." It would be fascinating to see some of those test results -- can you help? I also heard that PWK and Edgar Villchur had some debates -- were these in print or transcribed? Love to see them! 1 Quote Link to comment Share on other sites More sharing options...
boom3 Posted January 13, 2018 Share Posted January 13, 2018 I wish had copies, but I did see the curve PWK ran on the AR-3A. Yep, it was not nearly as flat as AR claimed, and it had a pronounced fall off above about 8 Khz. I think that AR's published system curves were all anechoic curves of the individual drivers spliced together 1 Quote Link to comment Share on other sites More sharing options...
JRH Posted January 18, 2018 Share Posted January 18, 2018 Yes, Paul tested everything he could get his hands on. The Altec A7 was the "target" when designing the LaScala. The museum has about seventy 3-ring binders chock full of curves going back to 1960. It is certainly a goal AT SOME POINT to sift thru them and make some available. PWK and Vilchur "went at it" in the October 1957 edition of Radio-Electronics magazine. 2 Quote Link to comment Share on other sites More sharing options...
Chris A Posted January 19, 2018 Share Posted January 19, 2018 A link to that magazine edition: http://www.americanradiohistory.com/Archive-Radio-Electronics/50s/1957/Radio-Electronics-1957-10.pdf 3 Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted January 19, 2018 Share Posted January 19, 2018 Thanks JRH and Chris PWK was one of those I would classify as having a “ Beatiful Mind “ who always made me think and so often opened my mind to new way of understanding the subjects he wrote about. miketn 1 Quote Link to comment Share on other sites More sharing options...
boom3 Posted January 21, 2018 Share Posted January 21, 2018 Reading that article reminded me of something I heard Paul say 20 or so years later, when he presented the curves he ran, including the AR 3A curves. He called Edgar Villchur "Edgar Vulture." I read somewhere (gee I hate that phrase) that in the 1930s Tannoy experimented with what Villchur later patented as "acoustic suspension" and gave up on it. At that time amplifier power was very costly and making low-efficiency speakers seemed counterintuitive. In a Dope From Hope, ("Whats a Watt?") Paul stated that 1 acoustic watt, radiating into "corner space" would equate to about 118 dB. Klipsch Heritage can handle that level with ease, although I daresay most listeners and rooms are overwhelmed long before that. I do know that my 4 Corn set up can produce an average of 102 dB with peaks as high as 106 dB in my rom, and that't the level at which my room and I cry Uncle. If you consider the best commercial audio reproducing chain that was available in the late 1950s, the Klipschorn was the component in the chain that, aside from the preamp, had the lowest distortion. I was not listening to Klipschorns then, but I bet that the audible differences between the Klipschorn and most other speakers were even more marked then than they are now. 2 Quote Link to comment Share on other sites More sharing options...
JRH Posted January 22, 2018 Share Posted January 22, 2018 One more addition. Electro-Voice took the AR patent to court and had it invalidated. We have communication in 1970 between Howard Souther (formerly of EV) and PWK regarding this. 1 Quote Link to comment Share on other sites More sharing options...
Chris A Posted January 22, 2018 Share Posted January 22, 2018 Jim, It was Allison and Villchur that wrote a JAES article on how modulation distortion isn't audible ("The Audibility of Doppler Distortion in Loudspeakers," AES 70th Convention, October 1981). This 2004 Stereophile article by Keith Howard pretty much reverses their views in favor of PWK on the subject of FM distortion...and no one since has apparently taken the ball on the audibility of AM distortion in woofers beyond what PWK did in the late 1960s. Since the two modulation distortion sources produce the same effect (significant higher order modulation sidebands). I assume that the Keith Howard's article also applies to that type of distortion source, too (AM distortion). The Klippel papers on measurement of nonlinear loudspeaker distortion will show those that are curious how these types of distortion are related. I particularly like the comments on the "edge" that FM distortion adds to musical sounds in the linked Howard article, above, even at very low levels...apparently at much lower relative levels than Allison & Villchur stated in their 1981 JAES article. It's still amazing to me how far other loudspeaker designers will go to defend small loudspeakers and the use of "long throw" woofers. Chris 1 Quote Link to comment Share on other sites More sharing options...
WMcD Posted January 23, 2018 Share Posted January 23, 2018 Look at page 102 of the mag for an advertisement for a Knight folded corner horn, Klipsch licensed. 2 Quote Link to comment Share on other sites More sharing options...
JRH Posted January 25, 2018 Share Posted January 25, 2018 Chris, You should have been in the Klipsch lab when PWK read the paper! 1 Quote Link to comment Share on other sites More sharing options...
Chris A Posted January 25, 2018 Share Posted January 25, 2018 I was just reading this article, which I think is apropos to the subject: https://www.technologyreview.com/s/610012/the-tricks-propagandists-use-to-beat-science/ I can bet what Mr. K's reaction was to the Allison & Villchur article. I've got the picture of how he reacted in my mind right now...( ). Chris Quote Link to comment Share on other sites More sharing options...
karlson3 Posted February 8, 2018 Share Posted February 8, 2018 in his "Audio League Report" 1955, I believe Julian Hirsch was using the AR-1 as a reference as it would play a reasonably clean 30Hz sine wave on the oscilloscope much cleaner than most of the high efficiency speakers (and the AR-1 was just as efficient at 30Hz as many of the larger speakers whose 30Hz response was quite a bit down from their flat passband sensitivity) The small box did make way for acceptable sized stereo installations. (fwiw, I do like Henry Kloss' KLH work a lot.) I've got great respect for PWK and personally think the K-400 is a better horn than sometimes gets credit. Quote Link to comment Share on other sites More sharing options...
Chris A Posted February 8, 2018 Share Posted February 8, 2018 FYI, For others that might not be conversant, it's modulation distortion that is the issue...not harmonic distortion that is seen in the type of tests that are described above. In order to see modulation distortion, two tones must be played at the same time: Chris Quote Link to comment Share on other sites More sharing options...
babadono Posted February 8, 2018 Share Posted February 8, 2018 On 1/18/2018 at 4:07 PM, Chris A said: A link to that magazine edition: http://www.americanradiohistory.com/Archive-Radio-Electronics/50s/1957/Radio-Electronics-1957-10.pdf Right in the middle of PWK's article there's a tube amp by Joseph Marshall. Is that the Marshall of Marshall Guitar amps? Quote Link to comment Share on other sites More sharing options...
karlson3 Posted February 8, 2018 Share Posted February 8, 2018 re: modulation distortion, the original Karlson 15" enclosure can exhibit a 10dB or better reduction in sidebands vs direct radiator. Quote Link to comment Share on other sites More sharing options...
Chris A Posted February 8, 2018 Share Posted February 8, 2018 35 minutes ago, babadono said: Right in the middle of PWK's article there's a tube amp by Joseph Marshall. Is that the Marshall of Marshall Guitar amps? I believe that you're looking for Jim Marshall. Quote Link to comment Share on other sites More sharing options...
babadono Posted February 8, 2018 Share Posted February 8, 2018 26 minutes ago, Chris A said: I believe that you're looking for Jim Marshall. Of course how silly of me An englishman publishing in an American Radio Magazine Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.