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What is the relation between ohms.......

Discussion in 'Amps and Cabs [BG]' started by Ibanezist, Apr 7, 2002.


  1. Ibanezist

    Ibanezist

    Mar 24, 2002
    What is the relation between speaker ohms, and amp ohms. Does it mean if the amp is rated at 350w@8 ohms and the speaker runs at 8ohms then the amp will be pumpin 350w's into that speaker?....that's probably not it, so please explain if you would.
     
  2. ndjx

    ndjx

    Oct 26, 2001
    MN
    That is correct. However, it would be the amp runs at 8 ohms and the speaker handles such and such wattage and 8 ohms.
     
  3. Ibanezist

    Ibanezist

    Mar 24, 2002
    Ok, but what if I had two seperate speakers, then what?
     
  4. Kurt M.

    Kurt M.

    Dec 11, 2001
    Reading, PA
    Hi,

    Resistance measured in ohms and impedance measured in ohms are many times confused. Impedance is a reactive function meaning it varies at any given frequency. Resistance, such as circuit resistance, is more or less a fixed term.

    Amplifiers are rated to deliver their power into a rated load (impedance). There are other factors such as the efficiency of the given driver (speaker) usually measured as signal to noise. The higher the signal to noise ratio of the speaker the easier it is to drive (more efficient).

    As to combining speakers you must calculate the impedance if using multiple speakers of different ratings. You can use the formula: total imp= (imp1)(imp 2)/imp1+imp2. So an 8 ohm speaker and a 4 ohm speaker combine: 4X8/4+8 = 2.6ohm total. If both speakers are the same it's easier to divide the impedance by the number of speakers. So 2 eight ohm speakers equal a 4 ohm load (8/2).

    Really it's not that big of a deal as long as your amp can safely drive the final load. Most stereo power amps can drive 2 ohm loads and up. Some bass rigs can't drive anything less than a 4 ohm load (my ampeg svt3 for instance). In the above example I couldn't drive the 2.6 ohm load without risking damage to my ampeg. The average stereo power amp could safely drive that load. There are other ways around this that get more complicated and many times involve rewireing the speakers.

    Hope this helps and I hope I didn't confuse you.
     
  5. Ibanezist

    Ibanezist

    Mar 24, 2002
    I think I understand, thanks.
     
  6. Kurt M.

    Kurt M.

    Dec 11, 2001
    Reading, PA
    Cool deal. I also gave you my thought on the Genz Benz stuff ----> see your other post.

    Later.