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8 8ohm speakers to a 4ohm load? help needed.

Discussion in 'Amps and Cabs [BG]' started by poor_gear_whore, Jan 15, 2014.

  1. I'm trying to wire an 8x10 for a friend. Cab needs to be 4 ohms. It's loaded with 8 ohm speakers. Anyone have a wiring diagram? I think I should be able to wire 2 sets of 4 speakers in parallel and then put those two sets in series for a total of a 4 ohm load, but I'm not 100% sure. Any help would be appreciated.
  2. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    (8+8) || (8+8) || (8+8) || (8+8) = 4Ω

    + = serial connection
    || = parallel connection
  3. Steve Dallman

    Steve Dallman Supporting Member

    Two sets of 4 in parallel and wire the sets in series. That works.
  4. Awesome! Thank you.
  5. will33


    May 22, 2006
    Imagine it as being a pair of 8ohm 410's, then parallel them together. Should have a DCR reading between 3 and 4 when you're done.
  6. You have two options and both of them have been described previously : A) series pairs and all pairs in parallel OR B) parallel pairs and all pairs in series. The primary difference will be what happens if one speaker fails. With option A, if one speaker fails its mate in series will stop working also. With option B, if one speaker fails all of the others will continue playing. If the cabinet is one that is constructed SVT-style with pairs of speakers in separate chambers then I think option A would be best because it has a safer failure mode. If one speaker in a chamber fails the other speaker in that chamber will likely follow its mate in short order if it continues to play. I think it is safest for it to just stop playing. If the cabinet does not have separate chambers then the decision is less clear for me but I would probably choose option A in that case too.
  7. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    For a graphic, here is option A [ (8+8) || (8+8) || (8+8) || (8+8) = 4Ω ]. +1 and -1 is for a speakon connector.

  8. That is exactly what I needed. Thanks a ton.
  9. tony89merc


    May 20, 2011
    So "Hypothetically" would this work if one wanted to build a "Franken Cab" with say 12 10's..... I was just wondering what that would sound like...
  10. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    If you built one like in the example above but with twelve tens, it would come out to 2.7 ohms. Why stop at twelve, even better would be sixteen tens, two 810 cabs, at four ohms each. A SVT can take 2 ohms so you could connect them both. Two 810 cabs would sound twice as good as one 810 cab.