effect of biwire on impedance

Discussion in 'Archived Threads 2001-2004' started by Lorenzo K, Sep 10, 2002.

  1. Lorenzo K

    Lorenzo K Agent

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    I currently have HTD level 3 mains which can be biwired and a pioneer 811s reciver. If I biwire, will the impedance of the HTDs change? They are rated at 8 ohms. The Pioneer manual states that I have to use speakers with impedance between 8 to 16 ohms. I have also read a thread here that said that the Pioneer have problems handling 6 ohms.
    Also, has anyone biwired the HTD 3? Did it improve sound quality?
    What do you guys think?
     
  2. Rob Rodier

    Rob Rodier Supporting Actor

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    Biwiring will not change the impedance.

    Biwiring made a big difference is my system. I recommend "true" biwire cables if you have the means.

    -rob
     
  3. Lorenzo K

    Lorenzo K Agent

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    What are true biwire cables? I thought biwireing was simply removing the metal connector between the two binding posts and running a speaker wire to each post from the same amp channel.
     
  4. john_focal

    john_focal Agent

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    yes... please more info on this, as I'd like to know how its done myself, what exactly it does vs. the metal connectors, etc..

    Thanks!
     
  5. john_focal

    john_focal Agent

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    cmon, someone out there knows about this [​IMG]
     
  6. Chu Gai

    Chu Gai Lead Actor

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    read a bit more about biwiring, which some may spell buy-wiring, here where at the end i illustrate a relatively simple procedure where, with the aid of some friends, you can determine if it made a positive benefit.
     
  7. Chris Carswell

    Chris Carswell Supporting Actor

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    I will agree with Rob that bi wiring made a big difference is my system. Where they really start to shine in big power hungry systems. The bass was tighter/stronger. The highs where about the same, maybe slightly sharper. I would also recommend "true" biwire cables. I first tried 2 runs of monster 16g. Basically I could of used the $ I spent as T.P. and had better results [​IMG] . I then got some Tara Labs Trio 416 bi wires ($159) that worked out great. When I got my big screen I needed a longer run so I again upgraded to the Tara Labs Prism Bi-wires ($275) and they were better.
    I'm selling my old Trio 416 biwires. If interested I could send them to you to try out. I also have a spare Prism bi-wire I can send as well.
    I had the VSX-810s and it would run my Kappa 6.1 (4ohms)fine until I hit -30db, then it would shut down [​IMG] Now I got smart and use Elite [​IMG]
     
  8. john_focal

    john_focal Agent

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    i'll be trying this at home for sure. Looking at true bi-wireing cable prices though, and the length's I need to run (diagonally across a 12 x13 room) make them out of the question at the moment financially.
    I'll do Chu's test, and post the results as soon as I can [​IMG]
     
  9. Peter Johnson

    Peter Johnson Stunt Coordinator

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    No, it will not change the impedance.

    Biwiring is electrically identical. All you are doing is moving the point at which the signal is "split" from the back of the speaker to the back of the amp.

    You *may* change the RLC characteristics...but no more than changing cables would.
     
  10. Lorenzo K

    Lorenzo K Agent

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    Thank you I will try it as soon as I can.
     
  11. Shion_ca

    Shion_ca Stunt Coordinator

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    As far as bi-wiring cables, if you leave the connects which join the binding posts on, you would probably effectively be using a larger wire guage. Once you remove the posts but still have both the wires running from the same amp, you'll have each set of cables driving loads each seeing a different load impedance.



    What good does bi-wiring do?

    Once the crossovers have been electrically separated, they present different impedance (loads) to the power amp within
    their passbands and outside of their passbands. The woofer and corresponding low frequency crossover section will
    present a low impedance at low frequencies and a high impedance at HF, while the tweeter section will present a low
    impedance at high frequencies, and high one at LF's.

    One argument about bi wiring is any improvement in the sound is due to the decreased total resistance of the cable, and this
    makes the speaker less prone to frequency response variations due to cable resistance. According to this view, simply
    running the two cables in parallel at both ends will do the same thing.

    With the electrical separation, differing currents will flow within the two cables that make up a bi-wire set. For the separate
    cable feeding the woofer section, a lot of current will flow at LF's but not much current at HF's, and the tweeter cable will
    have some current flow at HF, but very little at LF's. A division of labor has occurred with bi-wiring, whereby a single cable
    does not have have to carry the HF currents simultaneously with the LF current.



    Two things happen due to this:
    1. The losses in the cable due to "eye-squared-are" losses (current squared time the resistance equals voltage drop) are
    reduced for each frequency band, so that any tendency for the woofer to modulate the tweeter due to current draw is
    greatly reduced. This form of IM would be in lockstep with the original signal.

    2. The magnetic fields due to the HF and LF currents have also been separated out, and any tendency for them to inter
    modulate and cause sonic artifacts has been greatly reduced. This form of IM would be occurring both at the same time, and
    in a time delayed form due to mechanical resonance and motor/generator action.
     
  12. Chris PC

    Chris PC Producer

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    The impendance will not change much, but the speaker wires overall resistance will be less because bi-wiring does give the effect much like using thicker gauge wire. You are using twice the wire to send the same signal, so resistance in the speaker wire will be less. Speaker impedance does not change. If you use low cost speaker wire like me, then its ok to do. I don't recommend spending $100's or $1000's on speaker wire when bi-wiring or wiring any speaker. I bi-wired my speakers but I can't recall how much difference, if any, I noticed, but then again, it only cost me about $40.00 CAD. I know that during dynamic peaks, there is a high probability that bi-wiring will result in better sound.
     
  13. Chu Gai

    Chu Gai Lead Actor

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    just how big are these intermodulation distortions?
     
  14. Shion_ca

    Shion_ca Stunt Coordinator

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    Actually Chris I am under the impedance of a circuit is frequency specific. For instance a low pass filter has a very large impedance to a high frequency and a high pass filter a very large impedance to a low frequency signal. Thus instead of one line seeing the cumulative impedance of both filters each only seems the impedance for one section of the frequency band with. This would alter the reflected wave characteristics from the transmission line (cable) and thus alter how voltages are seen across each of the loads, thus directly impacting motion of the driver and thus sound. To what degree I am unsure but I am relatively sure that isolating each of the filters presents quite a different impedance characteristic to each line for most frequencies. Do you have reason to believe otherwise?
     
  15. Chris PC

    Chris PC Producer

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    Isolating the crossover filters does change things, although I'm not sure exactly how. Each line is connected to the same output on my receiver, so the receiver still sees both combined resistances, but how the whole circuit behaves, I cannot comment. I am no electrical expert. Not sure the total affect of all of this. I just understood that the crossovers are not used the same, the speaker has twice the wire to transmit the signal and I guess some other differences. It didn't cost much so I did it and it seems ok.
     
  16. Shion_ca

    Shion_ca Stunt Coordinator

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    Chu,
    You can checkout the numerical calculations for IM distortions on a sight called Sonic Design. something like sonicdesign.com (but not exactly) do a google search and look for +biwire +advantages, you should find all the math you want ; ) Tell me what you think when your done reading.

    Regards
     
  17. Robb Roy

    Robb Roy Supporting Actor

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