http://sound.westhost.com/cables.htm
Below excerpt is from this link. It has a scientific explanation on how cables can benefit in some speaker designs, in this case the Quad ESL.
"From a reader, I get dissent ...
I take issue with the statement that cables with a low (8 ohm) characteristic impedance offer no benefit they do. While it is true that twin cables, figure eight, are adequate for nominal 8 ohm loads over short distances there are a number of popular loudspeakers that are anything but nominal at high frequencies.
Two I have had dealings with are the AR11 and the Quad ESL (old model). Both of these drop below 2 ohms in the treble frequencies. The AR bottoming out at 5kHz and the Quad at 18Khz. The dips are fairly sharp and so the load impedance is highly capacitive on the way down and inductive on the way up. The frequencies are high enough to not worry good amplifiers but what about the response at these dip frequencies?
Twin wire cables all have significant inductance which increases in proportion to length. Their characteristic impedance is somewhere around 100 ohms. This means that response will only be flat over longer distances if the speaker is that impedance too a bit unlikely. I am not concerned with standing wave issues, they are not relevant.
With 10 amp rated twin flex over only 5 metres the response was down by 2.5 dB into one Quad ESL at 18 Khz, and 3.5 dB into the other speaker which had 8 metres. This was audible and unacceptable.
The only way to reduce cable linear inductance is to make the two wires talk to each other. Running in close parallel is a start, tight twisting is better but only by using multiple wires for each and interweaving can you really get the inductance down. Several cable makers have done this and sell them as low impedance cables, which is exactly what they are. The one I used was called Brand X, I know there are others.
Brand X uses two goups of 72 strands of enamelled wire plaited around a solid plastic core. The wires are coloured green and copper. It is a real chore to terminate needing a gutsy soldering iron to burn off the enamel.
Using Brand X the droop at either 5 or 18 kHz disappeared and the sound was distinctly better. There would be virtually no other way to solve the problem short of mono amplifiers sited next to each loudspeaker.
I am aware of only one drawback if you own certain amplifiers that are unstable with capacitive loads. The cable has about 9nF per metre of capacitance with little resistance or inductance which causes these amps to go into parasitic oscillation. The fix is simple, wind twelve turns of wire around a pen and put it in series with the beginning of the cable problem over. This tiny coil has far less inductance than even one metre of twin flex.
Author: It goes without saying that "Brand X" is not actually the name of these cables, but I am not about to give free advertising. This description of the possible issues with speaker cables is the first I have seen that makes some sense from a technical perspective, hence its inclusion. Although I have not measured the linear inductance of standard twin flex, there is sufficient evidence from many writers that there are indeed some detectable (and measurable) differences. With this in mind, and wanting to provide all the information I can, I have included this update. If you own speakers that present a highly capacitive load, or have deep "notches" in the impedance curve, I would take this information seriously.
