JBL 4310 wiring

Discussion in 'The Lansing Legacy' started by bikehomero, Sep 30, 2017.

  1. bikehomero

    bikehomero Active Member

    Messages:
    130
    Location:
    Frankfurt am Main - Germany
    Today i checked the wiring in one of my JBL 4310. All speakers are wired in phase but circuit diagram shows the tweeter out of phase. As my wiring is routed outside the box i'm able to change polarisation easy without disassembly. But i can not hear any difference in any case. As well measurement with my phone (Spectroid) doesn't show any significant differences.

    Does anybody know anything about the correct wiring?

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  2. toddalin

    toddalin Super Member

    Messages:
    2,213
    Suggest maybe you can find another model that uses the tweeter and se how that one is done. The LX-2, LX-8, and LX-11 all use this tweeter, but none really say with way the actual tweeter connects to the network.

    Also, see this link. Maybe the LE-20 is positive polarity so is wired backwards with the negative polarity components.

    http://reconingspeakers.com/faq/how-to-understand-jbl-reverse-polarity/

    A 61-band RTA would probably show the diference polarity makes around the crossover frequency even though you may not hear/recognize it.
     
    Last edited: Sep 30, 2017
  3. WaynerN

    WaynerN AK Subscriber Subscriber

    Messages:
    5,079
    Location:
    Minnesota
    Usually, they do not flip the polarity of the driver on a 6db per octave cross-over slope (simple, single capacitor), because of phasing factor. 12db per octave slopes do flip the drivers (normally).
     
  4. bikehomero

    bikehomero Active Member

    Messages:
    130
    Location:
    Frankfurt am Main - Germany

    Thank you for the link. Info from there is: "Control Contractor Series Studio Monitors: All 4300-Series models (except models 4311 and 4312L, R) are negative." So 4310 should be negative. I just checked out with the baterytest, in reality the woofer is positive. With 1,5V there is no movement at mid and tweeter.

    Maybe any owner of 4310 could check?
     
  5. bikehomero

    bikehomero Active Member

    Messages:
    130
    Location:
    Frankfurt am Main - Germany
    Research in heritage forum results in a find of this sheet:

    polarit├Ąt.JPG

    So i disassamled my 4310 again and checked the polarity direct on my speakers with a 1,5V battery. Woofer is possitive, midrange is negative. This is antithetical to the sheet where LF shoud be negative. Also the heading of the sheet seems wrong, as the 2015 is MF and LE20-1 is HF in reality. Cant see the movement of the LE20 so doubts will be continued.

    I think if my woofer is positive and the polarity of the midrange is negative they will substrate the frequences they put out. Under the aspect of missing coils in the EQ this seems fine to me.
     
  6. toddalin

    toddalin Super Member

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    2,213
    I think I've found your answer..., possibly.

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  7. bikehomero

    bikehomero Active Member

    Messages:
    130
    Location:
    Frankfurt am Main - Germany
    In this example evrything is in phase.

    B = Black input
    R = Red input (+)
    1 = Low frequency output +
    2 = Low frequency output -
    3 = High frequency output -
    4 = High frequency output +

    Can't find the answer.
     
  8. E.F.

    E.F. New Member

    Messages:
    3

    None of the images are showing up and I'm curious about an answer as well.
     
  9. twiiii

    twiiii Addicted Member

    Messages:
    5,920
    Location:
    west Texas
    With all the frequency shaping for the different drivers and impedance correcting its no wonder folks are confused. because the Tweeter uses a 3rd order filter and the mid something similar to a second order filters there is really no tight or wrong unless you run tests in an anechoic chamber with advanced test equipment to get the best results. According to JBL the mid should be wired with the polarity reversed. The way the speakers are oriented on the baffle may also determine the final results, too.
     

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