WMcD Posted March 4, 2006 Share Posted March 4, 2006 PWK occasionally mentioned this article. It is attached for your reading. On page 106 you will find "Fig.2 Exponentia horn with box-corner shaped final opening." This may well have been one of PWK's inspirations for the K-Horn. Sorry the quality is not a little better (margins) and it is not smaller. It is almost half a megabyte. Best, Gil Kellogg Means for Radiating.pdf Quote Link to comment Share on other sites More sharing options...
DizRotus Posted March 5, 2006 Share Posted March 5, 2006 Thanks again Gil for sharing another interesting article. Quote Link to comment Share on other sites More sharing options...
WMcD Posted March 5, 2006 Author Share Posted March 5, 2006 Thanks for the kind comment D.R. Such comments keep me scanning and posting. There is a nugget in there which not obvious. There may be someone out there who is interested. D-Man? Max? PWK in a patent cites to Kellogg for proper mouth size in a corner. Kellogg is estimating that by taking the point where the rate of expansion of the exponential horn is the same as the corner. They are not the same math function. The exponential is doubling area with every X distance. The corner is conical and area is the square of the X. However you can imagine an exponential horn with a round cross-section, and the corner scrunced into a cone, or megaphone. At some point the slope of the and size of the two match. That is what Kellogg is talking about in 1931. About 50 years later, Don Keele would write two important articles. One is Opitmum Mouth Size, which includes in fractional space like a corner, or an even more narrow conical horn. A supervisor of his recognize that Don had found something of great value and suggested he do more work. The other is "What's so Sacred about Exponential Horns." That is the genisis of constant directivity horns. Don Keele's analysis relies on complicated issues of tramsmission line analysis and reflection co-efficents or gamma. This was a mid or treble horn. Basically you can have good control of directivity with a conical horn. But it does not load the driver well. So you need a short exponential matching section, of some length,near the driver. He actually used a hyperbolic section and the classic exponential is a sub set of those expansions. There is the hard math. However, I was taken by the sketches by Don, in his paper. They show cross sections of the exponential and conical sections. They show that the point of transistion chosen by complicated math is very close to just matching size and slope, as Kellogg was doing. I cranked some of Don's math. It is basically what he sketches out. That is what Kellogg was talking about too. The bottom line is that hidden in Kellogg's work on bass horns is actually the same solution which was later found by Keele in treble horns by much more complicated math and computers. All of this seems more obvious in hind sight. But it is interesting that the ancient masters were way ahead of us. So smart. Gil Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 6, 2006 Share Posted March 6, 2006 Thanks Gil. I downloaded the article for later reading. I did a quick scan of it though... It has been said that there has been nothing new learned about horns since the 1950's - since then there have been only refinements. The "old" guys had it down, alright. It seems that PWK relied ALOT on Kellogg's work, for example the 1/18 wavelength "doubling point" is referenced in the 1945 Klipschorn patent. I've also seen the Kellogg patent (can't find it right now) of the corner triangular speaker shown in one of the figures. DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 29, 2006 Share Posted March 29, 2006 I knew I have seen that corner speaker design! here's the 1981 patent : 4229304 to Rebsch (I'll attempt to attach it). The device's appearence is instantly recognisable. Considering that Kellogg came up with the concept in 1931, that's only 50 years later... Also, Gil, there seems to be ALOT of nuggets (jewels, really) in the Kellog piece. PWK referenced this very article in several patents, including the last one (Gillum & Klipsch "MCM" patent in 1986) and the 1979 "Little-Bastard" patent. More than 50 years after the publication. Still valid. Great stuff! Thanks for posting it! DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 29, 2006 Share Posted March 29, 2006 Why don't these pics work?! I give up... DM Quote Link to comment Share on other sites More sharing options...
seti Posted March 30, 2006 Share Posted March 30, 2006 Gil, I really enjoy the articles from the early days of audio. In fact I have been trying to find info on P.A.G.H Voight after seeing the Voight Tractrix horn and Voight Cornerhorns in Hope, AR at the factory museum but have found very little information. Do you have any Voight articles or papers in the Gil Archives? Thanks again, Seti Quote Link to comment Share on other sites More sharing options...
WMcD Posted March 30, 2006 Author Share Posted March 30, 2006 We, yes, I have an "interview" of Voight by Bruce Edgar. Bruce made it up based on an exchange of letters. I'll post it Friday or Saturday for everyone's weekend reading. (Now I hope I can find it.) A few months ago I posted an article about a Voight horn found in a movie theater in England. It may be lost on the forum now. Did you see that? Best, Gil Quote Link to comment Share on other sites More sharing options...
seti Posted March 30, 2006 Share Posted March 30, 2006 We, yes, I have an "interview" of Voight by Bruce Edgar. Bruce made it up based on an exchange of letters. I'll post it Friday or Saturday for everyone's weekend reading. (Now I hope I can find it.) A few months ago I posted an article about a Voight horn found in a movie theater in England. It may be lost on the forum now. Did you see that? Best, Gil Cool looking forward to the article : ) I missed that article about the horn but now that the search engine is fixed I bet I can find it. Thanks again, Seti Quote Link to comment Share on other sites More sharing options...
seti Posted March 30, 2006 Share Posted March 30, 2006 Here it is and I had read when you posted. It is nice to be able to find things again. http://forums.klipsch.com/forums/thread/588453.aspx Quote Link to comment Share on other sites More sharing options...
ajsons Posted March 30, 2006 Share Posted March 30, 2006 Gil, I really enjoy the articles from the early days of audio. In fact I have been trying to find info on P.A.G.H Voight after seeing the Voight Tractrix horn and Voight Cornerhorns in Hope, AR at the factory museum but have found very little information. Do you have any Voight articles or papers in the Gil Archives? Thanks again, Seti Seti, I have some Voight related articles that I wil post when I figure out how to do it, with the new forum software. Quote Link to comment Share on other sites More sharing options...
ajsons Posted March 30, 2006 Share Posted March 30, 2006 From the Gramophone 1935 Quote Link to comment Share on other sites More sharing options...
ajsons Posted March 30, 2006 Share Posted March 30, 2006 P.Wilson 1935 Quote Link to comment Share on other sites More sharing options...
ajsons Posted March 30, 2006 Share Posted March 30, 2006 Page 2 P.Wilson Quote Link to comment Share on other sites More sharing options...
ajsons Posted March 30, 2006 Share Posted March 30, 2006 From Sound Practices Quote Link to comment Share on other sites More sharing options...
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seti Posted March 31, 2006 Share Posted March 31, 2006 Seti, I have some Voight related articles that I wil post when I figure out how to do it, with the new forum software. Thanks alot I have seen parts of that article but not the whole thing ; ) Quote Link to comment Share on other sites More sharing options...
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