RAFellows Posted November 25, 2020 Share Posted November 25, 2020 I bought these on eBay many years ago and don’t remember who made them and what they are called? It’s for the midrange horn to disperse the sound. 1 Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 25, 2020 Share Posted November 25, 2020 It is a JBL product (or a look-a-like). If it is original, then it might be worth some money. Don't take them to the dump. You can get more info over at the Lansing Heritage website. Good luck, -Tom Quote Link to comment Share on other sites More sharing options...
RAFellows Posted November 25, 2020 Author Share Posted November 25, 2020 Thanks Tom, Ill check JBL They do help the directness of the mid horns. Appreciate the quick response. Quote Link to comment Share on other sites More sharing options...
boom3 Posted November 26, 2020 Share Posted November 26, 2020 They are acoustic lenses, developed in the 1940s to improve the dispersion of horns. As horn design became more sophisticated, the extra expense and appearance of acoustic lenses was no longer appealing, and they were dropped. I think only JBL really promoted them, but they may have licensed the technology to others. Quote Link to comment Share on other sites More sharing options...
boom3 Posted November 26, 2020 Share Posted November 26, 2020 Acoustic Lenses Bell-Laboratories-Record-1949-10.pdfLike so many things in audio, these were devised at Bell Labs Quote Link to comment Share on other sites More sharing options...
moray james Posted November 26, 2020 Share Posted November 26, 2020 I have a set based upon the same design principals on my JBL L200B though these used flat plates rather than curved ones. They do work to disperse as stated however I find that they mess with the stage and the image of the horn and as such I do not use them. I think had they been a success that you would have seen more in production and for a longer period of time. I might add that similar but more complex versions of this concept were used by Beveridge electrostatic loudspeakers to provide a flat panel with wide dispersion characteristics. for those who might be interested. https://patents.google.com/patent/US3668335?oq=Beveridge+electrostatic+loudspeakers Here is some JBL information on what they produced https://jblpro.com/en-US/site_elements/2301-2390-2391-2392-2395-information Quote Link to comment Share on other sites More sharing options...
OO1 Posted November 27, 2020 Share Posted November 27, 2020 nope these are not JBL ---nor are they JBL reproductions or lookalikes , I have never seen this specific design pattern , could be a one off design Quote Link to comment Share on other sites More sharing options...
boom3 Posted November 28, 2020 Share Posted November 28, 2020 On 11/26/2020 at 10:26 AM, moray james said: I have a set based upon the same design principals on my JBL L200B though these used flat plates rather than curved ones. They do work to disperse as stated however I find that they mess with the stage and the image of the horn and as such I do not use them. I think had they been a success that you would have seen more in production and for a longer period of time. I might add that similar but more complex versions of this concept were used by Beveridge electrostatic loudspeakers to provide a flat panel with wide dispersion characteristics. for those who might be interested. https://patents.google.com/patent/US3668335?oq=Beveridge+electrostatic+loudspeakers Here is some JBL information on what they produced https://jblpro.com/en-US/site_elements/2301-2390-2391-2392-2395-information Thanks for finding the Beveridge patent. The original Beveridges were incredible speakers, and created a curtain of sound you could walk though, turn around and perceive the performance as if you were now in back of the performers. They are one of my two faves of all time (the Klipschorn of course being the other; have not heard Jubilees yet) 2 Quote Link to comment Share on other sites More sharing options...
garyrc Posted December 2, 2020 Share Posted December 2, 2020 JBL models Quote Link to comment Share on other sites More sharing options...
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