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Wiring cabs in series with proper phase?

Discussion in 'Amps and Cabs [BG]' started by oddio, May 1, 2003.

  1. Hmmm... perhaps I'm in need of coffee or something because I can't seem to get my head around a rudimentary problem this evening. I want to wire a cable for my two identical 4-Ohm cabinets to get an 8-ohm load, which should be easy enough. It struck me however, that I'm not certain (for some reason) how to do this correctly such that the cabinets are both in phase when wired in series. Damn. Anyone???
  2. geshel


    Oct 2, 2001

    Amp postive to Speaker 1 positive
    Speaker 1 negative to Speaker 2 positive
    Speaker 2 negative to Amp negative

    So the current would flow from the amp, into the + of the first speaker, then into the + of the second speaker, then back to the amp.

    You can think of it as "stacking" the speakers on top of one another electrically too if you want.
  3. ESP-LTD


    Sep 9, 2001
    - one + - two +
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  4. When you're working with raw speakers it's easy. Amp + to speaker (1) + Speaker (1) - to Speaker (2) + Speaker (2) - to amp -. However when you've got 2 boxes with 1/4 jacks it becomes a little more complicated. Here is what you need to do. Get 2 signle pieces of 14 ga wire, however long you may need them to be to reach from your amp to both cabinets. Next get 3 1/4" plugs (#1, #2, #3). Mark one piece of wire with a piece of tape and call it (+) the plain one will be (-). Cut the (+) in 1/2. Connect 1 side of the (-) wire to the - connector of plug #1 and the other side of the (-)wire to the + connector to plug #2. Connect one 1/2 of the (+) wire to the to the + connector of plug #1 and connect the other 1/2 piece of the (+) wire to the - connector of plug #2. You should now have a solid length of wire (-) with 1/4" plugs #1 and #2 connected to the + #1 and - #2 connectors on either end of it. You should also have (2) 1/2 pieces of wire connected to the - and + connectors of plug #1 and #2. Connect the + and - connectors of plug #3 to the remaining (2) 1/2 pieces of the (+) wire. You should now have a wire with 1/4" plugs on either end and a 1/4" plug in the center connected to the (+) wire. Plug the center plug (#3) into your amp and plug #1 and #2 in to the speakers. Good Luck
  5. Thanks to everyone, especially Greybeard for the detailed reply. Now that I've had morning coffee I can smack my forehead and say "of course!".

    That's pretty much what I was hoping to accomplish (1 cable/3 connectors). Using that setup I should be able to power my pair of 4-Ohm Acme Low B-2s with an iAmp 800, without risking the cabs.
  6. Be sure to check phasing with a battery.

    Industry standard phasing is + voltage applied makes the cone move forward (away) from the magnet assembly. Many earlier JBL are - (minus) forward, so always check for sure.