Why do you think Bi-Wiring improves the sound ?

Wrt Vandersteen, anyone who thinks it is a breakthrough that a magnetic field exists around current carrying wires and that they collapse and expand with the signal .... Hasn't taken a high school physics course.  It is laughable someone would put that in writing.


Absent magnetic materials surrounding the cable (don't use that cable collar :-)) that field is going to be quite linear hence no distortion products AND as the two wires run parallel and opposite direction the field strength is very small wrt the signal size. Two strikes, Vandersteen is out.

The crossovers in your speaker virtually split your cable into multiple cable of different frequency bands. Unlike the speakers themselves through mechanical non linearities and Doppler induced IM distortion or amplifier non linearities creating IM distortion, cables don’t have those mechanisms, certainly not within many orders of magnitude of anything else in the system. Resistance is not a non linearity so it does not contribute to IM distortion. As mentioned previously other than increasing gauge, makes no difference. Bi amping can reduce IM distortion which can justify multiple terminals.


I don’t believe or not believe either, I work on the soundness of the arguments and I have yet to hear a solid argument other than increased gauge for biwiring. If you are purposely trying to change the frequency response with cables then it would be easier with a biwiring setup, but cables make poor tone controls.

Do you just cherry pick one because it supports what you believe or fits your experience?

Funny, I feel the same about people who link to their blogs to appear erudite but then make fundamental errors or overly simplified generalizations that result in the wrong conclusion most of the time ... Hint, is the emitter resistor in the feedback or not?

^^^^ typical post of someone reading the title and inserting their 0¢.

Historically this was never provided for bi-wiring, it was provided for Bi-Amping to reduce IM distortion and/or tailor amps to frequency range.

Some consumers (and importantly also reviewers) seem to believe that it does, and prefer to buy loudspeakers which provide this option. Some manufacturers may therefore feel compelled to provide this option due entirely to these marketing pressures and little else.

Considering that the feedback changes the effect of this resistor and makes it approach 0 ....

05-03-2020 4:50pm

Hint, is the emitter resistor in the feedback or not?

Irrelevant in the models which show that changing 1 parameter affects response.

Truly good engineers are quite rare. Poor ones create "reports" like this one linked.

I will paste the link again for this thread so it is easier to find than go back and try to figure out which one it is:
https://www.qacoustics.co.uk/blog/2016/06/08/bi-wiring-speakers-exploration-benefits/

1) Where is the detailed equipment review. They say a "floor stranding speaker", then link to their Q40, but don’t explicitly say that is the model used, but then make a statement in the report about "Secondly at and above the typical cross-over frequency of 1 – 2 kHz, the intermodulation distortion has been reduced by up to 30dB.", -- BUT-- the speaker they linked to has a 2.3KHz crossover frequency. (The cross-over order has an impact on the back-EMF as well).


2) I couldn’t find any mention of the speaker wire used. Weird, really really weird in an article about Speaker Wire.


3) Very strange the amplifier is not listed, since this is pretty critical for a test like this. If I go out of my way to choose an amplifier with a really poor damping factor, then back EMF from speakers will have a bigger effect on the other speaker single or bi-wire, but you could make the differences larger with high damping factor. Weird to use what sounds like a "cheap" CD player/amplifier. Why not use high quality amplification?


4) 0 mention of the current probe and/or current probe amplifier used, hence no ability to validate it’s measurement performance and what it’s IM distortion is.

5) The unforgivable mistake of not measuring IM right at the drivers, after the crossovers, with single and bi-wire, which is the only proper way to isolate IM between single and bi-wire. (or better yet measure the IM at the output of the drivers).


6) Their claim of "IM" reduction is FALSE, and CANNOT be concluded, since they are not comparing what actually goes into the tweeters / woofers, but what they measured on the cables. IN FACT, if you add the Red line from Figure 6., to the Green line in Figure 7 (the two biwired measurements), you essentially get the same as the Blue line in Figure 6/7, especially where you would most expect it, i.e. 1-3KHz, in fact, not essentially the same, but almost exactly the same. That tells me that their claim in Figure 6 of reduced IM distortion (to the tweeter) is false since they have not established any of that current was flowing to the tweeter, and in fact, Figure 7, pretty much proves that no, that current was not flowing to the tweeter.

7) The 5 tones from 100-200Hz are flat on the CD, but are about 5-7 db different on the graphs, which makes sense on the single wire, or woofer graph where the impedance of the woofer in these frequencies could have a large impact, BUT, they should completely disappear in the Tweeter only graph, as in theory, that is only current in the Woofer wire. If the amplifier has a good damping factory, the voltage response will not change much, and the tweeter in a bi wire configuration should not see any difference in the amplitude of the tones.

8) Look at red graph in Figure. 6. HOW did a large NEW tone suddenly appear at 50Hz that is not in any other graph? That is simply not possible unless something changed.

9) Given the tweeter current draw from 300-900Hz is 90-100db down, the assignment of IM distortion products to single wiring in Figure. 7, where the distortion products are 60-70db down is an erroneous and impossible conclusion. More likely is test variation from temperature, voice coil heating, or ... the way they did the wiring which is not an actual comparison of single wiring to bi-wiring (it sounds good though doesn’t it) , but ... given 1-8, I am not surprising by 9,

"The single wired measurements were taken with two runs of speaker cable wired in parallel (speaker shorting pieces in place) and the bi-wired measurements were taken using the same arrangement with the shorting pieces removed. In this way both measurements used the same cross-sectional area of cable to eliminate any effect of lower resistance on our measurements."

10) ... what is the IM of the speakers?

I don't know the exact model, but for the progression, it is one of the rare times I would agree with Paul McGowan, as it is the same story I have heard from truly old-time audiophiles (my dad included) and matched the stories I read. First DIY, with SS base and tube for the mid/highs, and then speaker companies started to build the capability in. It never really took off, but it was a differentiator between cheap and "good".

The whole reason speakers started to have 2 sets of terminals was not for bi-wiring, but for bi-amping. Current starvation in the output devices, increased IM in the output stage from non-linear effects at higher currents, and IM from modulation of the power supply from bass frequencies is eliminated from the amplifier that only supplies the typically much lower current mids/highs. Voltage induced distortion effects at other stages in the amplifier will still occur of course, but traditionally this has been less of an issue.


There is no technical justification for "systems with properly designed passive crossovers make poor candidates for bi-amping", since the benefits are not for the speaker, they are for improvements in amplification. For amplifiers with lower THD at high power (typically because of high distortion near the 0-crossing), the high frequency amplifier will increase in IM, but will reduce in THD by riding on the high voltage bass signal. That same amp with an input passive filter for the highs can have sonically unacceptable distortion characteristics on real music.

Systems designed to be bi-amped typically do not have internal crossovers. Systems with properly designed passive crossovers make poor candidates for bi-amping.

The parallel loading of the additional drivers on the amplifier is almost always negative (see above) if your goal is accuracy and un-colored sound. Bi-Wiring only adds a very small amount of isolation, basically the impedance of one set of wires, which with competent wires is very little. Bi-Amping completely electrically (and back EMF) decouples the two driver sets.

driver response varies in combination with the driving amplifier and the parallel loads of the additional drivers.

Unless Vandersteen knows what your amplifier or wires are, there would be no way to predict the outcome, based on the rest of what you wrote. Products often incorporate designers "beliefs" which may or may not agree with reality.

I’ll trust the speaker designers’ opinions - ON THEIR OWN SPEAKERS. If Vandersteen has designed to benefit from bi-wiring, then the speakers might benefit from bi-wiring. If Dynaudio says "do not bi-wire," they probably won’t benefit from bi-wiring, no matter what Vandersteen says - after all he didn’t design the Dynaudios.