Electromagnetic distortion in multi-conductor cables

By mrgoodsound

I was not sure how to begin this article. Up until recently, I have been using stranded cable everywhere in my system. I was under the impression that the presence of stranded conductors was necessary for a good sounding system, and that solid core conductors had a monotonous and dull sound. This turned out to not be the case at all and in fact I have removed all multi-conductor stranded cabling from all of my systems. I am delighted with the results and decided they were worth sharing.

Before we go any further, let me clarify some terms. Actually, instead of posing the argument as solid core versus stranded conductors, it is more accurate to pose it as single conductor versus multi conductor cables.

The solid core (aka monocore, monofilament) cable is simple to understand. A single solid strand of wire is used for each conductor. In the case of an unbalanced interconnect, there are two conductors: a hot side (outbound route, plus) and a cold side (return route, minus). A famous example would be the 47 Labs Stratos interconnects. See the diagram above.

In a stranded (aka litz, multi-filament) cable then, each conductor would be made of several veins (or strands) of wire, carrying the signal in parallel to its destination. However, there is an important distinction to be made. The stranded conductor can behave electrically like a solid core cable if the individual veins are not electrically insulated from each other, i.e. by tinning the strand. A famous example would be the Belden 9497 wire. Such cables do not sound exactly like solid core cables, but they also do not possess the issue with multi-conductor cables elaborated below, at least not to the same perilous degree.

Electrical insulation can be in the form of a jacket or varnish on the wire, which causes the cable to behave like a multi-conductor system. Some manufacturers make unbalanced interconnects with many stranded conductors, sometimes as many as 8 or more, whereas only 2 are required. The sound of such a system is incredibly deceiving. At first, the sound becomes more 'comfortable', especially in the high frequencies. The 'air' of the recording is accentuated, giving an immediate impression of increased resolution. However, such a cable system seriously damages the clarity and intelligibility of music, and this often gives itself away only after living with it for a while and returning to a single conductor system (stranded or not).

Such multi-conductor systems are incredibly popular and prevalent in the 'high-end' industry specifically due to their 'comfortable' sound nature, which masks flaws in the connecting equipment. These effects can actually be desirable for some. I am reminded of the image of a Japanese manufacturer packaging speaker wires for different music genres, which non-audiophiles like to poke fun at. 

Also, they give the manufacturer something to write about in the marketing material, and give the consumer the impression that their dollars are going towards something (more conductors = more better). There are several manufacturers whose entire scheme lies in offering more conductors as you go further up their price list.

I have several anecdotes, the outcome of which caused me to identify and replace such cables in my system. I will share the first one, which was an a-ha moment that caused me to research the cause of this phenomenon (more later). I was using an interconnect from a high-end manufacturer that specializes in multi-conductor cables. My initial impressions of this cable were highly positive: there was a feeling of richer tonality, enhanced 'air' and separation. I left it there for a while, considered it a good purchase and thought nothing further of it.

One day I was listening to a performance Matthew's Passion (the exact recording below) on YouTube when I noticed something was extremely wrong. In the video, I could clearly see the 2nd and 3rd chair violinist playing, but I could not hear them. They had aurally vanished from the recording, to where I could only hear the 1st chair as distinct and the rest of the orchestra as an amalgamated 'background' whole. I was stunned, and I admit if I did not have the visual accompaniment to the music I would have been unlikely to notice this error, but I could not un-hear it. The individuality of the performers was significantly diminished (actually deleted, in this extreme example) as a result of what I consider to be blurring of the music in the time domain.

Understanding this interconnect was the most recent change in my system, my intuition led me to rip it out and replace it with a cheap unbranded one. My ears quickly adjusted to the decrease in richness and air, but I was delighted to clearly hear the action of the 2nd and 3rd chairs! The effect did not just stop at the strings, as the vocals showed great improvement in intonation and dynamic shading, so much so that my eyes welled up with tears at what I had been missing moments before.

Of course I did not immediately come to the conclusion that multi-conductor cables were evil from this experience. I was keen to blame this one cable (ironically I sold it to someone who liked it very much) and move on. However, subsequent identical experiments with cables from different manufacturers had identical results. The only design paradigm they had in common was in the use of multiple insulated conductors of stranded wire. The results were consistent whether the cable was an interconnect, speaker cable, USB, SPDIF, etc. I ended up removing multi-conductor cables from everywhere in my system. 

Rather than re-tell each experiment, I encourage attentive readers to conduct similar experiments at home. Please note that all conductors are subject to directivity and, if unmarked by the manufacturer, it is important to try a cable in both directions before final assessment.

Anecdotes aside, what explanation is there for this phenomenon? Like most phenomenon involving wire, I was ready to accept that this was without material explanation. One night I was reading the Anatoly Likhnitsky forum and stumbled upon a thread on the exact same topic. Likhnitsky conducted an experiment where he measured the compensation signal (electrical difference via common-mode suppression) between two pieces of wire connected in opposite directions between an amplifier and speaker. The first experiment was between two single conductor wires, whereas the second experiment involved a single conductor wire and a stranded litz wire.

Please note the text has been translated from Russian, and while I have done my best to preserve the original intent, some finer concepts may be lost in translation.

Results of the experiments

Two experiments were carried out with the aims:

1. To identify the audible "additive", for the case of compensation of signals at the output of two pieces of the same copper wire 1 m long and 0.6 mm in diameter, connected in the opposite direction.

2. Identify an audible addition in case of compensation of signals at the output of two wires of different types (in one case it was a piece of a copper monocore with a diameter of 0.6 mm and a length of 1 m, and in the other case it was a segment of a 32-core litz wire with a diameter of 1 mm and a length of 1 m)

In the first case, there is no AUDIBLE additive! That is, in the compensation mode, complete silence was heard from the loudspeaker, and at any distance from it, although during normal listening, the difference in the nature of the sound of this type of wire, depending on the direction of its inclusion, was very noticeable.

In the second case, an audible additive was found!

In the difference signal, an uncompensated signal was clearly heard, in the form of rustles correlating with music, the source of which, as it turned out, was the litz wire. The occurrence of this difference signal is explained by the electromagnetic effect in the stranded wire. Under the action of the Ampère force, the litz wire veins take part in micro movements in the magnetic field of neighboring veins, while, as a result of the action of the Lorentz force on the conduction electrons in the litz wire, an EMF is induced, which is recorded by a compensation meter.

Conclusions

The difference in the sound of identical solid conductors connected in opposite directions, which is reliably fixed by hearing, but not detected even with compensation measurements, is caused by non-physical phenomena, since these conductors cannot bear any specific, objectively measured distortions in a certain direction of connection, even purely theoretically. , otherwise a situation similar to 2+2=5 will arise (as D.Self figuratively put it). Our experiment only confirmed that nothing catastrophic happened in the world and still 2 + 2 = 4, however, the modern scientific paradigm, from our point of view, has been greatly shaken and, apparently, must be revised sooner or later. In it, first of all, a place must be found not only for the material, but also for the non-material,

The additive perceived by ear when comparing litz and monocore is explained not only by non-material, but also by little significant, but quite physical reasons, which, as it turned out, are easily detected during compensation measurements.