bkrop Posted January 27, 2003 Share Posted January 27, 2003 Why do the JBL hartsfield speakers have those plates angled towards the floor mounted in front of the mid/high horns on that and other models? Quote Link to comment Share on other sites More sharing options...
TBrennan Posted January 27, 2003 Share Posted January 27, 2003 bkrop---Those devices are acoustic lenses, they control the dispersion. JBL was real big into them in the 1950s and 60s, possibly because for marketing reasons they wanted to take a different approach than the multi-cell and radial horns used for dispersion control by Altec and RCA. Bart Locanthi designed the JBL lenses though the original idea, like so many horn ideas, goes back to Western Electric and Bell Labs. The lenses control dispersion in both the vertical and horizontal planes and were available in a variety of patterns. I own several horns with such lenses myself. One set throws an extremely wide 130 degree horizontal pattern. JBL replaced the lenses with constant-directivity horns in the 1980s. For more info on lenses check out the library at the Lansing Heritage site at www.audioheritage.org Quote Link to comment Share on other sites More sharing options...
bkrop Posted January 27, 2003 Author Share Posted January 27, 2003 Thank You very much! Quote Link to comment Share on other sites More sharing options...
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