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Help identifying a P.A. Speaker part......

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  • Help identifying a P.A. Speaker part......

    I was not able to actually get a picture, but in kids school auditorium, there was a horn driven speaker way up on the ceiling, that had some huge diffuser element. The horn was a standard looking horn and compression driver, but the diffuser had about 8 metal elements spaced about 1/2" apart from each other and was about 3 foot wide at most.


    The overall "diffuser" part was shaped almost like butterfly wing opened and I do not remember seeing things like this often.
    What is this part truly called?

    https://www.youtube.com/watch?v=Uqu56aICqYo

    Similar to the upper speaker element at the One minute mark on this video, but FAR larger.

  • #2
    It's a diffraction lens
    Brian Steele
    www.diysubwoofers.org

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    • #3
      JBL Acoustic Lens.
      www.billfitzmaurice.com
      www.billfitzmaurice.info/forum

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      • #4
        Based on your description I'm going to say it's a JBL 2395 slant plate lens, If everything is working in that system it should sound good.

        Even though they look like it those lenses do not aim the sound down. They actually widen the sound pattern horizontally by acoustically slightly delaying the sound exiting the horn/lens at the outer ends due to the longer path to exit the lens compared to the shorter path in the center, that's what gives the lens the sculpted shape.
        Those had something like a 120 X 50 degree pattern.

        If the school ever takes that system down don't let them throw it in the dumpster, those vintage parts are worth some money.
        Mike Caldwell
        http://www.mikecaldwellaudioproductions.com

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        • #5
          Look something like this

          Click image for larger version

Name:	JBL 2395 4560.jpg
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ID:	1428980

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          • #6
            Originally posted by seagrasser View Post
            Look something like this

            Click image for larger version

Name:	JBL 2395 4560.jpg
Views:	92
Size:	88.7 KB
ID:	1428980
            Those are what I was talking about!

            What drivers do you have on them?
            Mike Caldwell
            http://www.mikecaldwellaudioproductions.com

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            • #7
              Originally posted by seagrasser View Post
              Look something like this

              Click image for larger version

Name:	JBL 2395 4560.jpg
Views:	92
Size:	88.7 KB
ID:	1428980
              Yes, but without the box part.

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              • #8
                Sadly, not my photo, but this is a good representation of a JBL 2395 lens with a 4560 bass bin. Don't know what the super tweeter is in the middle or what compression driver is used on the lens. Interesting design for maximum dispersion.

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                • #9
                  Originally posted by seagrasser View Post
                  Sadly, not my photo, but this is a good representation of a JBL 2395 lens with a 4560 bass bin. Don't know what the super tweeter is in the middle or what compression driver is used on the lens. Interesting design for maximum dispersion.
                  The tweeter is a JBL2405 "slot" tweeter, good clean ones good for decent money these days.
                  Judging by the smooth cones on the 15 inch woofers I would guess they are JBL2220's
                  If the drivers on the 2395 lenses are of the same vintage they could be JBL 2440's or 2441's.

                  In the context of a big full range system the system in the picture would be the mids and highs, under that would be a stack of horn loaded
                  "W Bins" for low end.
                  Mike Caldwell
                  http://www.mikecaldwellaudioproductions.com

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