Power Output to speakers question

Discussion in 'Home Theater Projects' started by Ryan Wetenhall, Apr 14, 2003.

  1. Ryan Wetenhall

    Nov 17, 2002
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    Hey guys. Alright I have 5.1 surround sound. I have a sony STR-K740P receiver. The Power Outputs are as followed:

    Front: 80W/ch
    Center: 80W
    Surr.: 80W/ch.
    Subwoofer: 50 watts.

    What I want to do is hook up 4 more speakers. I would like to hook them up either via running audio cable into the other speakers or directly from the receiver. My question is, is this safe to do? I know that each speaker has a certain power output, so if I hook up more speakers into a port where other speakers are... will I fry my amp or speakers?
  2. Walt Park

    Walt Park Stunt Coordinator

    Nov 14, 2002
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    You dont want to do that. Your reciever doesnt have the logic to drive more than 5.1. If you wanted to add more speakers, you'd need self powered speakers, and extra pre-outs which I also dont think that reciever has, but that will mess up your imaging/staging.

    You cant really daisy chain speakers like that. It will sound bad if it works, but it probably wont. Most likely you'll need to keep an 8ohm load on each channel, which means the only way to do it is to use 2 4ohm speakers in series on each channel except center. That will really mess up imaging/staging.

    Anyway you look at it, this is not a good idea. It wont be louder, and it will sound bad, so there's no gain, just loss.
  3. Bob McElfresh

    Bob McElfresh Producer

    May 22, 1999
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    If you just hook black/red to new speakers on top of the old connections you are doing a PARALLEL hookup and will draw more current from your receiver. More Current means More Heat, More Heat means More Damage, More damage leads to the dark side... er... Reduced lifespan.

    If you want to try this, use a SERIES connection. You want to run 1 wire from the red/+ post on the receiver. Send it to the red/+ post on the first speaker. Then another wire comes out from the black/- post on that speaker to the red/+ post on the next speaker. Then the last wire goes from the black/- post on the second speaker back to the black/- post on the receiver.

    (Think of the wire as a water-pipe and it has to run to each speaker, then the next, then the next, then back to the drain).

    Radio Shack makes some nice Dual Bananas (2xx-308) and single bananas (2xx-306) that makes the hook ups easier and safer.

    But Walt is correct: if you are putting all these speakers in the same room, you stand a good chance of messing up the imaging and creating strange levels. Having different speaker distances, efficiencies in the speakers, etc., may be hard to compensate for.

    If you do this:
    • Try to put the 2 speakers for each channel at the same distance from the listening position. (Hint: measure to the tweeters)
    • Use a laser-pen to try and get them to be at the same angle.
    • Use a SPL meter at the listening position to try and level-adjust the volumes.
    • You said "4 more speakers". I'd start with 3 more speakers and double up on the front 3 channels. This will at least keep the front soundstage balanced.

    Good luck.

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