WMcD Posted February 6, 2010 Share Posted February 6, 2010 Attached is the subject article. Your weekend reading. Wm McD How Horns Work Revisited by Dr. Earl Geddes (compressed).pdf How Horns Work Revisited by Dr. Earl Geddes (compressed).pdf How Horns Work Revisited by Dr. Earl Geddes (compressed).pdf Quote Link to comment Share on other sites More sharing options...
greg928gts Posted February 6, 2010 Share Posted February 6, 2010 Thanks Gil. Doing a little research and found this http://www.bose.com/controller?event=VIEW_STATIC_PAGE_EVENT&url=/learning/waveguide_overview.jsp Uh oh. Greg Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted February 7, 2010 Share Posted February 7, 2010 WFGM: Very interesting for this morning. Waveguide vs horn with waveguide as the proper way to consider design? Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted February 7, 2010 Share Posted February 7, 2010 Uh oh. Greg "A waveguide several feet long could now be woven into a briefcase-sized enclosure, delivering sound with more clarity, depth and lifelike quality than a conventional component stereo system." Is it true!? A portable Klipschorn (well... semi-portable anyways...) [H] Quote Link to comment Share on other sites More sharing options...
boom3 Posted February 11, 2010 Share Posted February 11, 2010 "They realized that by mounting a loudspeaker in a tube, the motion of the loudspeaker would act as a waveguide, effectively transforming a small amount of input (air) into a large amount of output (sound). Drs. Bose and Short discovered that a waveguide could match the mechanical properties of a loudspeaker for efficient operation over a wide range of notes. " Hilarious. They rediscovered horn theory about 100 years after the fact. The so-called waveguide described is just an attempt at front-loaded transmission line, and probably not a very good one at that. It's really just a mass of air coupled to the driver to drop the resonance down, the essence of ye olde acoustic labrynith. OK, Bose. Keep rediscovering and mis-interpeting old, discarded technology, add a dollop of wishful thinking and wrap it in a cute little package. Write psuedo-sci-babble to make it "read well". Repeat as necessary. Quote Link to comment Share on other sites More sharing options...
boom3 Posted February 11, 2010 Share Posted February 11, 2010 Very interesting, thanks Gill. Gedde's acoustic lever (Patent 6,782,112) reminds me of an approach KEF has used. From my reading of the article, and the response, the argument seems to me to break into two parts: If you are interested in frequencies where the mouth of the device is comparable to, or larger than, the lowest wavelength of interest, waveguide theory should be your guide. (i.e., midrange and tweeter horns) If you are interested in frequencies where the mouth of the device will be small in comparison to the lowest wavelength of interest, horn theory should be your guide. (i.e., bass horns) Quote Link to comment Share on other sites More sharing options...
djk Posted February 12, 2010 Share Posted February 12, 2010 "Hilarious. They rediscovered horn theory about 100 years after the fact. The so-called waveguide described is just an attempt at front-loaded transmission line, and probably not a very good one at that. It's really just a mass of air coupled to the driver to drop the resonance down, the essence of ye olde acoustic labrynith." The Bose wave products most resemble the half-square antenna used by ham radio people. It's a good idea and I wish I had thought of it (first). Quote Link to comment Share on other sites More sharing options...
boom3 Posted February 12, 2010 Share Posted February 12, 2010 half-square, you mean like a Vee dipole? Quote Link to comment Share on other sites More sharing options...
Arkytype Posted February 12, 2010 Share Posted February 12, 2010 Gil, Good article. Here's an interview with Geddes by Voice Coil magazine. Lee Earlgeddesinterview.pdf Earlgeddesinterview.pdf Earlgeddesinterview.pdf Quote Link to comment Share on other sites More sharing options...
WMcD Posted February 12, 2010 Author Share Posted February 12, 2010 Thanks Arky. It looks like I've got a lot of reading to do. I'll have to track down his publications. Wm McD Quote Link to comment Share on other sites More sharing options...
djk Posted February 13, 2010 Share Posted February 13, 2010 "half-square, you mean like a Vee dipole?" http://rudys.typepad.com/ant/files/antenna_halfsquare_array.pdf Quote Link to comment Share on other sites More sharing options...
boom3 Posted February 13, 2010 Share Posted February 13, 2010 thanks...I will follow up after Mardi Gras! I built a EM loop out of copper pipe, just under 1 meter in diameter, to use with my SW radios....we have incredible QRM here...it helps, but I I have to have the loop right next to the radio so I can turn the tuning knob, also, the loop has to be seated in a wooden cradle to keep it upright on my desk. When not in use it hangs on the wall. Quote Link to comment Share on other sites More sharing options...
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