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Speaker ohms and how they affect cab rating

Discussion in 'Amps and Cabs [BG]' started by RobOtto, Sep 11, 2002.


  1. RobOtto

    RobOtto

    Aug 15, 2002
    Denton, TX
    One of my cabs is a Genz-Benz 2X10. As I have posted previously, I bought it used and the speakers inside are not original and my tech suggests getting Eminence because the existing Carvins can't cut it. (That is a different story)

    My question is this: The Carvin speakers in there now are 8ohm 200 Watts. How does that relate to my cab's ohm rating? Does having two, 8 ohm speakers still make my cab an 8 ohm cab? Or does 2, 8 ohm speakers make my cab a four ohm cab like daisy chaining two cabs together would?

    I ask because I am thinking of getting the eminence speakers and I want to get the correct pair. I can't find what was in my cab originally because genz-benz does not carry info on models they no longer manufacture.

    So in short: Two 8 ohm speakers = 8 ohm cab.... or Two 8 ohm speakers = 4 ohm cab?

    Thanks, and sorry for the long post.
     
  2. Two 8ohm speakers can only be wired one of two ways. In series for a total of 16ohms or in parallel for a total of 4ohms. There's no way to wire two 8ohm speakers together and come out with 8ohms. Guitar cabs are frequently wired for 16ohm impedance, but bass cabs are not, so I should imagine that your cab is wired for 4ohms.
     
  3. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    2, 8 ohm drivers in parallel = 4 ohms
    2, 8 ohm drivers in series = 16 ohms

    I depends on how its wired. But normally It would be wired in parallel and be a 4 ohm cab.

    What are the dimensions of your box? This is prudent info because you will need to try to match the drivers with the box volume. You dont want to just stuff any speaker in there and eminence makes a bunch of different models.
     
  4. RobOtto

    RobOtto

    Aug 15, 2002
    Denton, TX
    So how many ohms are the speakers in a 4X10? They would have to be 32ohms each in parallel for the cab to be rated at 4ohms?

    I think I am missing something.

    An eight by ten would be impossible to create that way, wouldn't it?
     
  5. K-Frog

    K-Frog

    Feb 6, 2002
    Camden, AR, USA
    series-parallel my friend.

    Think of two pair of speakers,
    each pair is two speakers in parallel with each other,
    each pair is wired together in series.

    8+8 = 4
    8+8 = 4
    series together for 8 ohms.

    if 4 ohm drivers were used, you'd get a 4 ohm cab.

    HTH, kenny
     
  6. zombywoof5050

    zombywoof5050

    Dec 20, 2001
    Four 32 ohm speakers in parallel would give you 8 ohms.
    Four 16 ohm speakers in parallel would give you 4 ohms.
    With an 8x10, I imagine they use a combination of series and parallel to achieve what they want.
     
  7. A 4 Ohm 8x10" would probably be:

    8+8=4
    8+8=4

    Wired in series to make 8, then

    8+8=4
    8+8=4

    Wired in series to make 8. Then, both 'halves'(4 speakers each) would be wired in parallel to give a total of 4 ohms.