Series and parallel confusion.

Discussion in 'Speakers & Subwoofers' started by PeterK, Sep 7, 2004.

  1. PeterK

    PeterK Supporting Actor

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    I was looking at some old threads and came across one involving wiring 7.1 with only a 6.1 capable reciever. What I've always done when wire more than one speaker to one ouput is basicaly wire the first speaker in, then stick the next speaker as if the first speaker was a reciever output. I think from what I've read is that that is not the preffered way of doing it because I will half the omh rating of the speakers. I may have this backwards so please correct me.
    Also one more thing that I always thought was odd. Why is it harder for a reciever do drive speakers with lower ohm ratings. It is my understanding that ohms are a unit of resistance correct? if so, would have less resistance make it easier for source (reciever) to power the load (speakers) I haven't really done much electricity in physics yet so I may be way out in right field on this one. [​IMG]
    thanks.

    if someone could provide diagrams of what a series and parallel circuit looks like in terms of a 2 speaker reciever situaltion, that would clear things up instantly I would imagine
     
  2. Wayne A. Pflughaupt

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    Parallel
    [​IMG]


    Series
    [​IMG]


    Regards,
    Wayne A. Pflughaupt
     
  3. PeterK

    PeterK Supporting Actor

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    So which is prefered? I am going to run 2 8ohm speakers but my reciever is only 6 ohm rated. if I wired series that would be easier on my reciever correct?
     
  4. Charlie C

    Charlie C Stunt Coordinator

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    what happens when you take the positive feed from each channel and hook those to the speaker leads. Ive done this many of times but never knew what it did to the ohmage.
     
  5. Wayne A. Pflughaupt

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    Yes. Naturally an amp designed to put out 100 watts isn’t working hard at all putting out only 40 watts. However, since those speakers are underpowered, the tendency will be to run that channel at max, so you won’t have much in the way of dynamics.

    If you want to go series a viable option would be to use a pair of 4-ohm speakers. The 8-ohm load wouldn’t reduce the amp’s power as much – maybe 75-80 watts.

    Regards,
    Wayne A. Pflughaupt
     
  6. PeterK

    PeterK Supporting Actor

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    Well, I will put them in parallel first and if my receiver is struggling too much then I will go series and accept the low volume. these are rear speakers so they aren't really that important anyway.
     
  7. PeterK

    PeterK Supporting Actor

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    Ok, I am planning on hooking the backs up and testing them before I put run the cable. If I just want to see if my rears will be able to handle the load of the 2 speakers can I only Hook up the rears. Does each channel in the reciever have it's own amp? or do I have to hook up all channels to see if I am overworking the amp(s)?
     
  8. Wayne A. Pflughaupt

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    Yes, each channel has its own amp. However, usually the protection circuitry is global. In other words, if one channel gets into trouble, the receiver goes into protect mode and shuts down all channels.

    Regards,
    Wayne A. Pflughaupt
     
  9. Seth Paxton

    Seth Paxton Lead Actor

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    Plus, max efficiency of an amp (any amp) is reached when the load resistence (speakers) MATCHES the source resistence (the amp).

    So even putting an 8 ohm on a 6 ohm amp will result in some loss of maximum power efficiency.


    Also remember that if given the choice between an amp that is too weak or too strong always go with TOO STRONG. When an amp is too weak it can clip, meaning that it can't reach the max power points on the wave/curve and will actually flatten rather than continuing the curve up (or down) until the curve comes back below the max limit.

    Think of a sine wave in which the tops and bottoms have been smashed flat. Those points are very harsh on the speaker and are more likely to result in damage than overdriving them will.


    Back to the parallel speakers - just think of it this way, 0 ohms is a short, the same as simply connecting the ground to the hot directly. So the more you reduce the resistence the more you move toward shorting your speaker wires together. And I'm sure its clear how nasty that would be.


    And yeah, the whole amp typically shuts down if one line gets shorted. I've had mine do it by accident when a wire got loose and, luckily, the amp goes right off immediately (Denon).



    Rubber soles as protection are because rubber is a poor conductor which means very little amps required to drop voltage across it (if a flow can even be achieved). Amps are what do the damage (that's the actually flow of electrons) so less flow is a good thing in such cases.
     

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