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Bi-Wiring from a technical point of view

Discussion in 'Home Cinema Speakers' started by Reiner, Mar 5, 2002.

  1. Reiner

    Reiner
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    I had just a heaty discussion on another forum if bi-wiring does give any benefit which can be electrically measured.
    So I would like to know what the experts think or if you can support/dismiss this theory:

    We assume a bi-wire capable speaker with a DC resistance (not impedance) of 8 Ohm. Inside we find a simple x-over design, i.e. a capacitor in series with the tweeter and an inductor in series with the mid/bass driver, both of which are connected in parallel.

    We connect (single wire) the speaker to the amp using a 2.5sqmm cable.

    Now the argument goes like this: the DC resistance is mainly defined by the low pass as the high pass (due to it's capacitor) will have an extremly high resistance.
    Therefore we cannot assume it's a parallel connection where 1/Rt = 1/Rh + 1/Rl applies. (Rt = total, Rh = high, Rl = low)
    Or based on that formula we could also say that Rt is actually Rl (in parallel wiring the total resistance will be smaller than the smallest single resistance. In this case it sums up to nearly 8 Ohm)

    If we now bi-wire (using an additional 2.5sqmm cable) we disconnect the high from the low pass, thus the low pass is connected via a 2.5sqmm cable and the high pass is connected via a 2.5sqmm cable.

    Now we could assume that we have doubled the diameter of the cable, but based on the claim that the high pass DC resistance is actually nearly infinite it can be neglected. As well remember the cables are only joined at one end (at the amp), indeed the cables are not parallel and thus the cable resistance won't change either.

    Can you still follow me?


    Now we conclude that the low pass is still connected via 2.5sqmm, single wired or bi-wired, hence the current flowing through is the same (the voltage can/will not change as in both cases they are connected in parallel).
    Thus there would be no advantage in seperating the two.


    I agree that we are not talking about DC and that we need to consider the impedance, but to make things simple and following the explanation above we could calculate using the DC resistance instead. Or not?

    Hope you get what I mean, sometimes I can't express myself that well ... :blush:
     
  2. Lowrider

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    This wont be of any help technicaly, but notice some high end speaker manufacturers, for instance Wilson and Sonus Faber are only supplying one pair of terminals...
     
  3. Lowrider

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    I forgot to mention TAG, this is what they have to say:

    "After extensive research it was discovered that at a very high quality level the potential benefits of multi-wired terminals for speaker cable connections were outweighed by the losses incurred in their implementation, e.g. additional contact interfaces and electrical connection straps."
     

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