Why do you think Bi-Wiring improves the sound ?

Hmm, nobody took a note of the posted link in this thread. That explains why bi-wire works and the science behind it. With measurements, graphs and all.
Rather clever test track and method they have composed to use to be able to measure and show the effect of Intermodulation in a same cables single (wires) configuration and in bi-wire configuration. 

It is making a scientific proven difference but if it is detected by ear or not. That are determined by several OTHER factors. So audiophiles that are able to hear the benefits have some of the other factors aligned (room, speakers, gear and so on).


Used test method:

Notes

The test tone CD was played using an all in one CD player/amplifier set at half volume into a pair of floor-standing speakers. The current probe measurements were analysed using TrueRTA via a Tascam US144 USB audio interface. 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.

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/

There is a couple of analogies that are used in the explanation. That is needed for me anyway to be able to grasp the complex working of it. That may need to be re read and let sink in.

So we see that there is much more than some false logic that will cloud our thinking and make the individual more comfortable to put for example this specific effect aside. When it is not properly understood or known.

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?

heaudio123
you have an interesting argument , I'm going to read the link and your response at least one more time .
I'm going to assume that they " qaucustics " used thier own speaker and cables .

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

... and the load changes the feedback.

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.

Systems designed to be bi-amped typically do not have internal crossovers. Systems with properly designed passive crossovers make poor candidates for bi-amping. Amplifier response varies with the load and driver response varies in combination with the driving amplifier and the parallel loads of the additional drivers.

This is quite easy to demonstrate:
2 identical power amps y'd from the source.
Drive the LS full range, bi-wired and bi-amped. There are 3 distinct responses, all easily identifiable.

Some drivers make poor bi-amping candidates without either active or passive equalization other than crossover slopes.

There is no, and never has been, any free lunch.

@heaudio123
I don't understand why you are so antagonistic. My examples are stated necessarily simplistic to communicate concepts. Are you a manufacturer? Audio sales?
"atmasphere, as someone who designs amps (for many applications), I cannot agree at all with your comment w.r.t. amount of feedback and sounds profile." from  https://forum.audiogon.com/discussions/it-looks-like-a-debate-to-me?page=2

What amps, pray tell!