Speakers in series

Discussion in 'Amps and Cabs [BG]' started by mljohn, Aug 12, 2000.

  1. mljohn


    Jul 16, 2000
    There's an article in BP (AUG '00) that shows how to make your own cable to run speakers in series(instead of rewiring your speakers). I would like to run four 4 ohm enclosures for mains to increase the sound level without using another power amp.

    Current PA setup:
    500W per channel amp
    2 15 enclosures
    2 monitors

    Has anybody ran a similar setup? Pros and cons of running in series?

    Why aren't these cables commercially available?
  2. The answer is quite simple. Running cabs in series is possible only when you're using exactly the same cabs. This is due to the fact that speaker cabinets are very complex loads, from the amplifier point of view. Different cabs in series will influence each other, which is, obviously, bad.

    IF, and only if you plan to use 4 of exactly identical 4 ohms cabs, you end up driving 16 ohms, reducing the amplifier power to 1/4, as compared to a 4 ohms load. But it will sound o.k.

    Hope this helps.

  3. funkastorious


    May 26, 2000
    Mpls, MN.
    I'll take a stab at this as well.

    Your 500 watt amp (you didn't mentioned that which impedance) should have stereo outputs. (right and left). It also has a minimum OHM rating. For most power amps, it's 2...but most bass amps are 4, so let's just assume that.

    Most bass speaker cabs are going to be either 4 or 8 ohm config. So, you need to be equally concerned with your minimum load (ohms) on your amp as you are witht eh actually sound.

    In a perfect world, we would buy new speakers each time we bought an amp to make sure that everything matches up, that that's not the case.

    So, let's say you have a power amp with a minimum load of 4 ohms, but you have (2) 4 ohm cabinet that you would like to run. If you plug one cab into the the right and the other into the left (parallel), you cabs are going to make the amp run in down the 2 ohms. Which, in out case, is not a good idea.

    So, you can either 1) run one cabinet or 2) wire them in series that actually increases the load on the amp. So, if you use the nifty cable as seen in BP, you will take 1 of the outputs of your power amp and get (2) jacks for your cabinets. Of course, they REALLY forgot to mention that 90% of aftermarket cabinets already have jacks ready to accomodate series or parallel wiring. In series wiring, you can hook amp-cabinet-cabinet rather than using a y connector....so you don't have to make the fancy cable. Don't understand why they didnt' mentioned that.

    On the downside, you are going to lower the output of your amp (in this scenario) to 8 ohms. So, that 500 watt amp ain't going to blowing 500 watts. Therefore, you may be better off just using one of those 4 ohm cabs rather than robbing power.