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Possible to lower Ohms rating?

Discussion in 'Amps and Cabs [BG]' started by Sound Guy Paul, Jul 15, 2002.


  1. I was wondering if it was possible to change the Ohms rating of a cab. I am thinking about getting a Carvin 4x10, but it is 8 Ohms, and the 1x15 I want to get is 4 Ohms. I dont know exactly how many ohms that totals out to, but I want to get the most power out of it, and the minimum on my power amp is 2 Ohms. Anyway to do this?

    Also I have a Mackie 1400i power amp, and it says that in stereo it pushes 700 watts a channel at 2 Ohm, is that 2 Ohm combined, or each cabinet separate?
    Thanks for any help
     
  2. ZuluFunk

    ZuluFunk

    Apr 14, 2001
    Pennsylvania
    Usually, with stereo amps, you can run a 4ohm cab and an 8ohm cab at the same time. You just have to adjust your power to match the load per side.

    Also, a 410 cab at 8ohms is probably wired in series to get that impedence. I would suggest that you could have it rewired to a 4ohm load if you need.

    If you keep things the way they are, you can run with the Mackie. Each channel is independent. So it doesn't matter if you have an 8ohm on one and a 4ohm on the other.

    Call Mackie to make sure, that's the way it is on my QSC.
     
  3. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    No, I don't think you can rewire that cab for 4 ohms. Practically speaking, the most common way of getting 8 ohms out of four drivers is to make all of the individual speakers 8 ohms, then wire them series-parallel. I'm sure this is what your Carvin has. If you were to wire them all in series, you'd get 32 ohms; if all in parallel, 2 ohms. (No 4 ohms.)

    Your cab can't have four 16 ohm drivers, because then the impedance choices would be 4 ohms for parallel, 16 ohms for series-parallel, and 64 (!) ohms for series. (No 8 ohms, you see.)
     
  4. geshel

    geshel

    Oct 2, 2001
    Seattle
    The Mackie 1400i puts out 700w per channel if the load on *each* channel is 2 ohms.

    You could use the two cabs on separate channels yes. You'll have more options though if you get two cabs of similar impedance.

    8ohms and 4ohms in parallel works out to be 2.67ohms, so you could hook them both up on one channel safely. However, the 4ohm cab would get twice the power that the 8ohm cab gets, which probably isn't desirable.
     
  5. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Changing the impedance of a speaker cabinet is usually not a practical thing to do. However, if the 8-ohm 4 × 10 is made up of 8-ohm drivers in a series-parallel configuration, they could probably be re-wired to make a 2-ohm load.

    You've got a two-channel amp, so there's no problem with using two cabinets of different impedances. If you put one on each amp channel, you can then control them independently to get the sound you need.