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mystery 15 inch in weirdo cab.

Discussion in 'Amps and Cabs [BG]' started by Josh Ryan, Sep 13, 2002.


  1. Josh Ryan

    Josh Ryan - that dog won't hunt, Monsignor. Staff Member Supporting Member

    Mar 24, 2001
    I have become the owner of a completely unlabeled 1x15. How can I test it to see:

    1- ohms
    2- watts RMS
    3- watts Peak



    is it possible w/o destroying it?


    edit, I know ohms can be checked, but I forget how!
     
  2. Ohms is easy. Get an ohmmeter. It measures at DC, so the impedance is about 1.25 times the measured resistance.

    Power can't be measured, because maximum power is defined as: ' highest possible input power before breakage ', so you'll have to destroy the speaker to measure it's power rating.

    I guess you could drive the speaker louder and louder and measure the temperature of the coil every time, but nah....... impossible
     
  3. Josh Ryan

    Josh Ryan - that dog won't hunt, Monsignor. Staff Member Supporting Member

    Mar 24, 2001
    Ok thanks! It was free, so I guess if I cook it, it's not the end of the world anyway.
     
  4. is it in a cab?? if so either take the back off the cab/or unscrew the speaker and see what it says on the back of the speaker...
     
  5. Josh Ryan

    Josh Ryan - that dog won't hunt, Monsignor. Staff Member Supporting Member

    Mar 24, 2001
    that's the odd thing, it says nothing! It has a black sticker that's half peeled off.
     
  6. dooberheim

    dooberheim

    May 17, 2002
    Missouri
    On the ohms, an 8 ohm speaker will measure about 5.6 ohms with a DC multimeter, 4 ohm will be about 2.8 ohms.

    You can roughly estimate the power handling of the speaker by its construction, weight, and voice coil size. See if the speaker basket is stamped or cast. Stamped baskets are used in lower powered speakers. Lower powered speakers also have smaller voice coils. Take the speaker out and weigh it. If it weighs only about 10 pounds or so and has a 1.5 - 2 " voice coil it is probably not good for more than 100 watts (perhaps a hi-fi or full range speaker). If it is 20 pounds or more with a 3-4" voice coil and a cast basket it is probably a high power bass speaker good for 400 watts RMS or more.

    Just approximations, but you get the idea.

    DK