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Thread: Black=positive

  1. #1
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    Black=positive

    http://www.pispeakers.com/JBL_Polarity.pdf

    So is it true that with these transducers, black is positive? I guess I'm new to the party...

  2. #2
    Senior Member Lee in Montreal's Avatar
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    Quote Originally Posted by wrager View Post
    http://www.pispeakers.com/JBL_Polarity.pdf

    So is it true that with these transducers, black is positive? I guess I'm new to the party...
    Party is over since the mid 1980s if I am not mistaken. Then JBL joined the bandwagon. A 1.5v battery is your best friend to determine the polarity of your speakers.

  3. #3
    Senior Member louped garouv's Avatar
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    how does one determine the polarity for a compression driver?

    impulse testing?

  4. #4
    Senior Señor boputnam's Avatar
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    bo

    "Indeed, not!!"

  5. #5
    Senior Member pos's Avatar
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    Quote Originally Posted by louped garouv View Post
    how does one determine the polarity for a compression driver?

    impulse testing?
    Yes, holmimpusle for example will show you the thing immediately
    I was surprised when I installed some truextent diaphragm to see that they also follow the "old" reversed logic, whereas their doc tell the opposite!
    http://materion.com/~/media/Files/PD...nDiaphragm.pdf
    The "+" on their diaphragm is in fact a "-", so the doc should read "positive voltage on - terminal moves diaphragms towards phase plug"...
    This is good for compatibility with older diaphragms that these are supposed to replace, but I wish their doc at least tell the truth, as I had to reinstall my diaphragms...

  6. #6
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by pos View Post
    This is good for compatibility with older diaphragms that these are supposed to replace, but I wish their doc at least tell the truth, as I had to reinstall my diaphragms...
    I only see this about polarity:

    Polarity ........................................... Positive voltage at + terminal moves
    .................................................. ..............diaphragm towards phase plug


    I guess that could be correct as well as ambiguous, as in: For the vintage JBLs the positive terminal is the black one and possibly with Radians it is the red one? I don't actually know about the polarity of Radian drivers. My point being, they are saying that if you use the driver's "positive" terminal, you get a forward movement. They are not saying which terminal is the positive terminal.


    Widget


  7. #7
    Senior Member pos's Avatar
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    Yes they are: there is a "+" on the diaphragm, so the doc *is* wrong
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  8. #8
    Senior Member grumpy's Avatar
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    Just be careful to ensure that the test system (mic/pre/line/software) has a
    physically verifiable polarity. E.g., baseline with a low frequency driver that
    DC can be applied to, and the excursion observed... noting if it matches
    the polarity of the measured pulse with the test system.

  9. #9
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by pos View Post
    Yes they are: there is a "+" on the diaphragm, so the doc *is* wrong
    So you are saying that a positive voltage on the "+" terminal of the coil does not produce a diaphragm motion towards the phase plug as the document clearly states?


    Widget

  10. #10
    Senior Member pos's Avatar
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    Yes, I am positive about that

    When I installed the diaphragms I wanted to keep the original behavior of the JBL driver so I connected the black terminal to the + on the truextent to get a reverse polarity, but it was in phase...
    I know my test setup respects polarity so I am pretty sure about this (and also the fact that now that I reconnected the red terminal to the + the popularity is the same than my other JBL drivers)

    I just recheck while writing this post: my truextent with red terminal connected to the + on the diaphragm has the same polarity than my 2435.

  11. #11
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by pos View Post
    Yes, I am positive about that

    When I installed the diaphragms I wanted to keep the original behavior of the JBL driver so I connected the black terminal to the + on the truextent to get a reverse polarity, but it was in phase...
    I'll contact Truextent and see what they say about that.


    Widget

  12. #12
    AMACNEE
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    Curious as to how to use a 1.5 volt battery to test polarity?

  13. #13
    Junior Member Mr Wizard's Avatar
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    Quote Originally Posted by AMACNEE View Post
    Curious as to how to use a 1.5 volt battery to test polarity?
    Connect a wire to each speaker terminal.
    Touch one wire to the negative side of the 1.5 volt battery terminal and hold it in place.
    Touch the other wire to the positive side of 1.5 volt battery terminal, if speaker cone pushes
    outward, the wire on the positive side of 1.5 volt battery terminal is the speakers positive terminal.
    If you flip the wires on the the battery the speaker cone will pull inward.

    It helps to have a fresh battery. Also it is easier to see a woofer cone move than a tweeter diaphragm.

    Mr Wizard

  14. #14
    Administrator Robh3606's Avatar
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    Do not use a battery to check polarity on a compression driver. Cones only say mids and woofers where you can see the movement.

    Rob
    "I could be arguing in my spare time"

  15. #15
    Junior Member Mr Wizard's Avatar
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    Quote Originally Posted by Robh3606 View Post
    Do not use a battery to check polarity on a compression driver. Cones only say mids and woofers where you can see the movement. Rob
    I stand corrected. Also it is easier to see mids and woofers move when checking polarity. Do not use a battery to check polarity on a tweeter/compression driver. . Mr Wizard

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