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Thread: JBL L150-A Help

  1. #1
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    JBL L150-A Help

    New Owner of a pair of L150-A Speakers. Question I have is I just found out that these are wired out of phase (woofer moves in and not out when positive is applied to the red. Is all the drivers run out of phase or just the woofer?
    any advantage to correcting this so it would be in phase?

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    JBL has some drivers that move in with + at red driver terminal and some that move out with + at red driver terminal. But they seem to have settled on the wire with the black stripe going to negative post on each driver, I think it's green/black on the 150A.

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    Senior Member RMC's Avatar
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    Hi vintage,

    Polarity conventions have changed over the years, however look at number 7 on the pic shown. Regards,

    Richard

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    Quote Originally Posted by JeffW View Post
    JBL has some drivers that move in with + at red driver terminal and some that move out with + at red driver terminal. But they seem to have settled on the wire with the black stripe going to negative post on each driver, I think it's green/black on the 150A.
    Jeff I looked at the crossover and solid wires are all positive and striped are negative. The question was is there a benefit to reversing the wires on the woofer so it would move out with a positive input?

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    Quote Originally Posted by RMC View Post
    Hi vintage,

    Polarity conventions have changed over the years, however look at number 7 on the pic shown. Regards,

    Richard

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    Richard,
    Question was is there any harm or benefit to running the positive to the black so the woofers move out with a positive input verses in with a positive

  6. #6
    Senior Member grumpy's Avatar
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    So...

    1) They were designed this way.

    2) If you want try to establish a certain absolute polarity, and you think you hear a difference, just swap the wires at the cabinet speaker terminals or at the amplifier. It won't harm anything, but I suggest you do both speakers if interested (although it's educational to do just one as a test, to hear what an out of phase speaker pair sounds like).

    3) If you only swap the polarity of the woofer and change nothing else, you -will- affect the way the woofer and mid interact in the crossover region...
    still won't damage anything, but it may sound different and have a different frequency response than stock. Benefit? Try it and and see. They're your speakers

  7. #7
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    Quote Originally Posted by grumpy View Post
    So...

    1) They were designed this way.

    2) If you want try to establish a certain absolute polarity, and you think you hear a difference, just swap the wires at the cabinet speaker terminals or at the amplifier. It won't harm anything, but I suggest you do both speakers if interested (although it's educational to do just one as a test, to hear what an out of phase speaker pair sounds like).

    3) If you only swap the polarity of the woofer and change nothing else, you -will- affect the way the woofer and mid interact in the crossover region...
    still won't damage anything, but it may sound different and have a different frequency response than stock. Benefit? Try it and and see. They're your speakers

    Thank you. I will leave them as they are.

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