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yet another ohm question

Discussion in 'Amps and Cabs [BG]' started by hetsscaryguy, Jun 1, 2004.

  1. hetsscaryguy


    May 22, 2004
    somebody should really make a faq page on ohms and impedence but anyway my question is if i have a 300w amp with 4 ohm impedence and i have a cab the is over 600w handling power will i get my 300w power or is it the amp output that gets halved or nearly halved? this subject reallly confuses me :confused:
  2. Transverz

    Transverz believer of the Low End Theory

    May 3, 2004
    Los Angeles, CA
    hey hetsscaryguy,

    This whole impedance thing (in general) is not that hard. First of all, the question you are asking (the way you have put it, at least) is missing a vital piece of information: How many ohms is the cab rated at?

    Your amp is 300W @ 4ohms MINIMUM. This means that if you are running a 4 ohm cab, then you will get 300W out of it (or so your manual says). Although you should consult your manual specs, if the cab is 8 ohms, you will most likely run 175watts or something like that.

    Getting back to what you might have been really asking: What's up with the power handling? Well, in general, a cab that handles 600watts and gets 300watts (if you the cab is indeed 4 ohms) is good enough. But really, it depends on it's efficiency rating how "good" or how much volume you are gonna get out of it. This should be in your cab specs sheet. A bit more complicated, but yeah. Even 200watts in a 600watt rated cab can be enough, in general.

    For example, my Avatar B410 is rated at 1400watts. I am running 350watts through it at 4 ohms and it is loud enough for me. That's about 1/3 of the cabs watt handling. Your mileage may differ.

    Questions? :ninja:

    *edited for more accurate information* :D
  3. stu FORD

    stu FORD

    May 22, 2004
    if a head spec sheet sais:
    480w@4 ohm
    320w@8 ohm

    and i want to put two cabs on (under) this head what should theyre rating be?
  4. Transverz

    Transverz believer of the Low End Theory

    May 3, 2004
    Los Angeles, CA
    If that is ALL the spec sheet says (not possible to do 2ohms), then the lowest impedance (and most watts you can get from the amp) will be from two 8 ohm cabs (which get you down to 4 ohms). Yeah, you could do two 16 ohm cabs, I suppose but you would get 320watts instead of 480watts. And anyway, unless you specifically ask for it, there aren't very many cabs nowadays that come in 16ohms.