Multimeter to read ohms, were to stick "prongs"

Discussion in 'Amps and Cabs [BG]' started by Special_Ed, Feb 13, 2005.

  1. Special_Ed


    Oct 3, 2004
  2. Special_Ed


    Oct 3, 2004
  3. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Plug your speaker cable into the cab, touch the red to the tip of it, and the other behind the black ring.


    Edit: Note though, when you get this readout, it's not going to be pretty, but an "in the ballpark" measurement, cos you'll be getting it at a pre-set frequency, where as the cabs (I think!) are usually average over useable frequencies.
  4. ESP-LTD


    Sep 9, 2001

    If you examine your speaker cable, it probably has 2 contacts. Put one lead on each one. It should read 6.x ohms for an 8 ohm box and 3.x for a 4 ohm. If you have a crossover and horn, this may not work at all. The right way is to pull the connectors off the speaker and measure there.

    An ohmeter measures DC resistance. You are interested in AC Impedance; that's why the 8 doesn't exactly = 8.
  5. DC resistance and AC impedance are unrelated... its a coincidence that they are anywhere near each other.

    - Andrew

  6. They aren't really unrelated as DC resistance is a component of the impedance.....

    The number quoted on a speaker is the DC resistance plus the 'average' AC impedance over the frequency range except they drop the complex notation.

    At any rate you can expect an 8 Ohm cab to measure 5-6 Ohms DC and a 4 Ohm one to measure between about 2.5-3.5 Ohms DC.