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Thread: JBL K140

  1. #1
    Heaven_4u
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    JBL K140

    Hello, I am new to this forum.

    When I was DJ some years ago I had a set of JBL speakers K140 with double reflex cabinet.

    I still have in my possesion 2 K140, 2 passive crossover and 8 tweeters.

    I am wondering if I could use those speakers to build a subwoofer. I am looking for specification to built such a box and what type of amp I could us to drive it.

    This sub will be use as part of a pro audio set up.

    Thanks for any help.

    Richard

  2. #2
    Senior Member jim campbell's Avatar
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    K140

    K140 are much happier in bass guitar cabs,especially mine

  3. #3
    doctordata
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    K 140 Sub

    I build a K140 sub with one driver in a 57 litres ported box , tuned to 20 Hz combined with a electronic filter as published in "Luidsprekers fabels en feiten"
    ( That's Dutch for "loudspeakers Myths and facts" ) ISBN 90-70160-46-3 The electronic filter contains only three Op-Amps , 9 resistors and one capacitor and is based on the patented "ACE" principle by K.E.Stahl . I use the system for 4 years now, combined with a 150W RMS amp module in my Denon and Tannoy Home theatre and I'm still impressed with the stunning performance of this combinaton , down to 20 Hz - 3dB and loud enough for my 10 x 6 metres living room .

    Happy converting ,
    Cheers ,
    Rens
    Brisbane

  4. #4
    Senior Member edgewound's Avatar
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    Quote Originally Posted by doctordata
    I build a K140 sub with one driver in a 57 litres ported box , tuned to 20 Hz combined with a electronic filter as published in "Luidsprekers fabels en feiten"
    ( That's Dutch for "loudspeakers Myths and facts" ) ISBN 90-70160-46-3 The electronic filter contains only three Op-Amps , 9 resistors and one capacitor and is based on the patented "ACE" principle by K.E.Stahl . I use the system for 4 years now, combined with a 150W RMS amp module in my Denon and Tannoy Home theatre and I'm still impressed with the stunning performance of this combinaton , down to 20 Hz - 3dB and loud enough for my 10 x 6 metres living room .

    Happy converting ,
    Cheers ,
    Rens
    Brisbane
    That's amazing....20Hz @ -3dB with a K140 in a 2 cubic foot box!
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  5. #5
    RIP 2011 Zilch's Avatar
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    We want the details!

    [Patent number would be good....]

  6. #6
    Senior Member tomt's Avatar
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  7. #7
    Senior Member Eaulive's Avatar
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    Quote Originally Posted by edgewound View Post
    That's amazing....20Hz @ -3dB with a K140 in a 2 cubic foot box!
    If he has a low shelving filter that can give him 20dB boost starting at 50Hz.... it may work.
    Although not very loud
    Last edited by Eaulive; 09-01-2011 at 06:19 PM. Reason: typo

  8. #8
    Senior Member Lee in Montreal's Avatar
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    I have on my shelves a Kef Kube 200. It is a Linkwitz transformer that adds about 24db at 10Hz. Just be carefull when you play film soundtracks. But a lower level the sound is incredible. It transforms any decent speaker into a grunty subwoofer.

    It does something like that.

    Basic transformer
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    Marchand WM8
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  9. #9
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    Never maid to be subs and won't play at medium to loud levels beleive me!

  10. #10
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    Question

    I recently discovered some old pa speakers my dad has are K140's. Checking them to see if they still worked I, noticed they were "pulling", instead of "pushing". The polarity is correct, I was just wondering if they were designed this way, or if there is a problem. I tried to find info online but I couldn't get any good answers. The two speakers are used in two seperate boxes as "mids" for his pa system. I hope some of the pros here can help.


    Thanks

    My bad I posted in the wrong topic...

  11. #11
    Senior Member Lee in Montreal's Avatar
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    While the universal norm was that the red post was positive,for reasons that evade me, JBL had decided at the time that the black one was the positive one. Therefore, if you use a battery with the + side into the black post, then the cone should more forward.

  12. #12
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    Aaahhh, that would explain it. Has JBL always done this with all their speakers past, and present?

  13. #13
    Senior Member Lee in Montreal's Avatar
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    Quote Originally Posted by Tiger View Post
    Aaahhh, that would explain it. Has JBL always done this with all their speakers past, and present?
    http://reconingspeakers.com/2010/06/...erse-polarity/

  14. #14
    Senior Member paragon's Avatar
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    K.E. Stahl

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  15. #15
    Senior Member paragon's Avatar
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    K.E. Stahl

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