Some guy at Carvin just told me...

Discussion in 'Amps [BG]' started by positivechris, Jan 4, 2013.


  1. positivechris

    positivechris

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    that wiring two 4 ohm speakers in series would not produce an 8 ohm cab/load.

    Am I a moron?

    TIA
  2. Handyman

    Handyman

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    No, you are not. Wiring them in series get you 8, and parallel gets you 2.
  3. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

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    No. Of course it won't be 8 ohms when measured by a VOM across the terminals.

    <edit> OK, maybe Carvin guy not so dumb.
  4. chucko58

    chucko58 Supporting Member

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    Wired in series, any break in the wiring shuts them all down. That's why we usually wire in parallel.
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  6. two fingers

    two fingers Loud Mouth Know It All Blowhard Gold Supporting Member

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    I am going to guess he misunderstood what you were saying. I have had several conversations with those guys and they have always been at least up to par if not great. Again, it's just a guess, but I think there's some sort of communication gap there.
  7. okcrum

    okcrum in your chest Supporting Member

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    That's why we have solder. ;)
  8. Handyman

    Handyman

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    My suspicion is that the other guy was probably thinking about daisy chaining multiple cabs, which does in fact put the speakers in parallel.
  9. Mystic Michael

    Mystic Michael Hip No Ties Supporting Member

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    That's also why we wire speakers in parallel... :eyebrow:

    MM
  10. Handyman

    Handyman

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    Quite a few 4x10 and 4x12 cabs are wired in series/parallel configuration from the factory. I'd be more worried about getting struck by lightning.

    How often have you seen a speaker cab's wiring fail, or melt a voice coil? Sure wouldn't keep me up at night.
  11. positivechris

    positivechris

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    Interesting. Anybody got a link for some reasonably priced 16 ohm 10 inch speakers?

    Again, thanks for the help.
  12. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio!

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    Also, because amplifier outputs are primarily voltage sources, the variations in impedance among series-wired loudspeaker drivers will affect the signal that the other driver(s) receive. And vice-versa.
  13. positivechris

    positivechris

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    Explain this, please. If I'm running a series 8ohm and a parallel 8 ohm cab into a 4 ohm amp would this create problems for the amp?
  14. landau roof

    landau roof Reupholstered User Supporting Member

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    Measured DC resistance does not equal nominal impedance.
  15. Mystic Michael

    Mystic Michael Hip No Ties Supporting Member

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    There! See? :p

    MM
  16. Handyman

    Handyman

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    An ohm meter simply measures DC resistance, while the impedance rating of a speaker also includes AC impedance created by the voice coil's inductance.

    Basically, a speaker's resistance should always read somewhat lower than its nominal impedance because of this.
  17. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio!

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    All of the mechanical attributes of the loudspeaker system--moving mass/inertia, spring action of the suspension, air loading and its variations due to the enclosure, driver resonance, etc.--also become part of the impedance.
  18. Handyman

    Handyman

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    Fair enough. A speaker is a motor, after all. The impedance vs frequency curves certainly don't look much like a plain old inductor.
  19. georgestrings

    georgestrings Banned

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    This - in fact, nearly all 410s are wired series/parallel, and it never seems to be a problem for them...


    - georgestrings
  20. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

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    Probably. If that's the case, you need a special cable to daisy chain two cabs in series. I've made a couple of them.

    What he said. Usually, an 8-ohm speaker impedance will read somewhere between 5 and 6 ohms on a DC ohmmeter.
  21. B-string

    B-string Supporting Member

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    You need to explain "4 ohm amp". If it is a SS head that says "4 ohm minimum" then two 4 ohm or a 4 ohm and 8 ohm cab in parallel will exceed the minimum load (4 ohm and 4 ohm= 2 ohms, 4 and 8=2.667 ohms). 8 and 8 in parallel = 4 ohm load and you are good, run them in series and the load becomes 16 ohms still fine but less power will be available from the amp. If it is a tube amp you should match the speaker cabs closely to the amps needs if at all possible.

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