Need help matching ohms

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by CS'56, Jun 7, 2006.


  1. CS'56

    CS'56 Member

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    I have a 15W pro junior. The speaker jack is 8 ohm. I'm building a cab to house a 10 and a 12 inch speaker. I already have an 8 ohm 10 inch. Would it be better to get a 8 ohm or 16 ohm for the 12 inch speaker to go with my 8 ohm 10 inch speaker?
     
  2. John Phillips

    John Phillips Member

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    I'd get a 16-ohm. Firstly, it will give a total load closer to what the amp wants (5.33 ohms not 4 ohms); and secondly, the power will be distributed 2/3 to the 10" and 1/3 to the 12", which should help even out the sensitivity difference between the two - generally, 10s are about 3dB quieter than 12s for roughly equivalent types (although there are variations).
     
  3. CS'56

    CS'56 Member

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    Thanks John.
    Are there any websites that would show me the proper way to wire them?
     
  4. John Phillips

    John Phillips Member

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    It's very simple... connect the tip terminal of the jack to the positive terminal on both speakers (you can either go from the jack to each speaker, or from the jack to one speaker and then to the other speaker, it doesn't matter), and connect the ring terminal of the jack to both negative terminals. That's it :).
     
  5. doctorx

    doctorx Member

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  6. hasserl

    hasserl Member

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    Interesting information John. I don't like mixing impedances amongst speakers. My first response would have been to recommend getting another 10" along with the 12" with both being 16ohm, giving you the correct impedance to start with, and better balance between the two. It also gives you a chance to purchase a pair of speakers you want to work together. That would be the best way to do this. But if you're looking to cut cost and use what you've already got, then it looks like John's answer is a good one.
     

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