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Wiring in series &/or parrallel

Discussion in 'Home Cinema Speakers' started by HeadBanger, Jun 8, 2004.

  1. HeadBanger

    HeadBanger
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    I have done a search on this and understand that running in parrallel halves the impedance and series doubles.

    I am about to run 2 sets of rears in series (8ohm). Now if I bi-wire as well (parallel) does that (in theory) mean that I'll end back up at the 8ohm impedeance?

    Anyone's help here would be much appreciated before I fry one of my speakers!!!!
     
  2. jeff-o

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    I think there's a bigger danger of frying your amp.....

    And no, I don't think you'll arrive back at 8 ohms, either. You'll have a total of four speakers, right? Two for rear left and two for rear right? You may need some impedance-matching transformers in there....
     
  3. HeadBanger

    HeadBanger
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    Yes four rear speakers in all. So would I be better off wiring in series (ie doubling the impedance & halving power to each speaker) but forgetting the bi-wire then?
     
  4. jeff-o

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    Hmmm, can your amplifier handle 4 ohm loads?
     
  5. HeadBanger

    HeadBanger
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    Yes - runs 4ohm to 16ohm.
     
  6. Nimby

    Nimby
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    Why would you want to run four speakers instead of two? :confused:

    Nimby
     
  7. jeff-o

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    Hmmm, then you should be able to run the pairs in parallel after all...
     
  8. HeadBanger

    HeadBanger
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    Nimby - it's fairly common to run more than one set of surrounds - it gives a more wrap-around surround.
     
  9. alexs2

    alexs2
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    As long as the speakers are genuinely 8 ohms(bearing in mind that certain models may be rated nominally at 8ohms,but dipping down to less than 3 ohms at certain points),and the amp is also genuinely capable of handling prolonged runs with 4 ohm loads at high power,then you should have no problems.

    Not many amps are capable of doubling their power output into 4 ohm loads,and fewer still will cope with less than that.....just be sure the sums are right!
     
  10. Nimby

    Nimby
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    I certainly wouldn't consider running pairs of 4 Ohm speakers in parallel. The low impedance would probably kill most amps. 2 x 8 Ohms in parallel is a severe enough test when most speakers dip to a low somewhere in their response.

    I overheated a couple of amps running 8 Ohm DIY passive subs in parallel with 8 Ohm speakers. Fortunately they just tripped the thermal protection and came back on when they had a chance to cool.

    Series connection is much safer if you check the phase of all 4 surround speakers carefully. (Or your bass will just vanish and you'll get some wierd effects) :blush:

    It sounds like a recipe for disaster from the WAF point of view. :suicide:

    Nimby
     
  11. alexs2

    alexs2
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    Pretty sure I didnt recommend anything of the sort there,as I was referring to running 8 ohm speakers in parallel,and being careful to ensure that their impedance curve is reasonably smooth,and that the amp will cope with the load.

    The heaviest load for most amps,and coincidentally the place here a number of speakers have their lowest impedances,is in the low bass region,where current demands are highest,and for many amps,the ability to both deliver and control are at their lowest.

    Some amps are fine with this sort of thing,but that ability usually equates with cost,huge power supplies,and often Class A running.
     
  12. Nimby

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    I must have expressed myself badly alex2. I don't disagree with anything in your excellent post. :)

    Just adding my own experiences to emphasise the dangers of parallel running.

    Doing anything that risks the kit for only a potential improvement in sound quality must always be a calculated risk. The more information available to help make such a risky decision the better.

    I doubt the average AV fan can confirm an acceptably smooth impedance curve in the absence of published graphs. You're also perfectly right regarding the average amp's abilty to drive low impedances.

    My hope is that this thread will save somebody jumping on the four speaker bandwagon without doing their homework first. Hearing that you can bung 4 speakers at the back sounds exciting if you can afford the extra boxes. But this idea should be approached with great care IMO.

    Ideally a series/parallel speaker arrangement would bring the impedance back to a sane level. But that means 8 rear speakers! :devil:

    Nimby
     
  13. HeadBanger

    HeadBanger
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    Many thanks for your posts guys.

    I won't be running 8 rear speakers (balancing the impedance between series & parrallel) so I think that I'll stick to the safer route (ie 2 x 2 in series).
     

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