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Swr 4x10 8 Ohm to 4 ohms

Discussion in 'Amps and Cabs [BG]' started by Nighttrain1127, Mar 19, 2005.

  1. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    I have a Swr workingmans 4x10 that is eight ohms. I want to rewire it to 4 ohms but it all runs together into one input not a regular harness . how would I go about changing this Without chopping up the wiring harness if possible? :bassist:
  2. You can't, the math doesn't work out. Your cab has four 8ohm drivers in it (most likely) and there's no way to wire four 8ohm drivers to equal 4ohms.
  3. JSCHRO7376

    JSCHRO7376 Commercial User

    Feb 23, 2004
    Los Angeles County, CA
    Owner, Schroeder Cabinets

    You have to get 4 new speakers with a 16 ohm impedance each to achieve a 4 ohm cabinet; re wiring won't work.
  4. illidian


    Jul 2, 2004
    He could do it.

    What are the ratings of the speakers? If eight ohms, keep reading. If sixteen, skip to paragraph two. If four, skip to paragraph three.

    Parellel series (four plus four is eight for parellel, two eights in series is four).

    Parellel (sixteen divided py two [for one couple of speakers] is eight, wired in parellel with another eight would be four ohms).

    Series parellel (four divided by two is two, two and two wired in series is four).

    Perfectly possible.

    [size=small]Disclaimer: technical names of "series" and "parellel" may be mixed up[/size]
  5. I'm sorry to point this out but I gotta do it. Four plus Four? These are eight ohm speakers, not four!

    Sorry, nice try! :D
  6. By the way parallell/series and series/parallel would produce the same results with four drivers.
  7. pdxmar


    Feb 13, 2005
    you need to find the impedence of the speeakers......usually some combination of series and or parallel will get the desired result with 4 speakers. If they are all 8 ohm speakers getting a 4 ohm load is not possible......2 ohm is no problem however.
  8. illidian


    Jul 2, 2004
    Figures, my math was right but I get caught when I don't proofread. :p

    Let's try that again...

    I believe people have said it's not possible. If I'm wrong then someone can do the math for me. :bag:
  9. ironfist


    Feb 5, 2000
    If you have an 8 ohm 4x10 cabinet with four individual drivers each with an 8 ohm impedance (most likely by far), than it cannot be wired to be a single enclosure with a nominal 4 ohm rating.

    The cab is wired in series/parallel. Each pair of speakers is wired in series, then the two pairs are wired together in parallel (or vice versa). This gives you a nominal load of 8 ohms.

    If you wired the whole thing up in series, you'd have a cab with a nominal impedance of 32 ohms.

    If you wired the whole thing up in parallel, you'd have a cab at 2 ohms.

    The only exception would be two wire two of the speakers in parallel and leave the other two unhooked. That would give you four ohms. :D
  10. Well lets see. Assuming 8 ohm drivers:

    All series. 8+8+8+8=32
    All parallel. 1/(1/8+1/8+1/8+1/8)=2
    Series/parallel 1/(1/8+1/8)+1/(1/8+1/8)=8
  11. No 4-driver 8-Ohm cabinet can be wired to be 4 Ohms without new drivers.
    The only possible drivers for a 4-driver 8-Ohm cab are 2 Ohm, 8 Ohm or 32 Ohm and there isn't a combination of them that will result in 4 Ohms.

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