Science that explains why we hear differences in cables?


Here are some excerpts from a review of the Silversmith Audio Fidelium speaker cables by Greg Weaver at Enjoy The Music.com. Jeff Smith is their designer. I have not heard these cables, so I don’t have any relevant opinion on their merit. What I find very interesting is the discussion of the scientific model widely used to design cables, and why it may not be adequate to explain what we hear. Yes it’s long, so, to cut to the chase, I pulled out the key paragraph at the top:


“He points out that the waveguide physics model explains very nicely why interconnect, loudspeaker, digital, and power cables do affect sound quality. And further, it can also be used to describe and understand other sonic cable mysteries, like why cables can sound distinctly different after they have been cryogenically treated, or when they are raised off the floor and carpet.”


“One of the first things that stand out in conversation with Jeff about his cables is that he eschews the standard inductance/capacitance/resistance/impedance dance and talks about wave propagation; his designs are based solely upon the physics model of electricity as electromagnetic wave energy instead of electron flow.


While Jeff modestly suggests that he is one of only "a few" cable designers to base his designs upon the physics model of electricity as electromagnetic wave energy instead of the movement, or "flow," of electrons, I can tell you that he is the only one I’ve spoken with in my over four decades exploring audio cables and their design to even mention, let alone champion, this philosophy.


Cable manufacturers tend to focus on what Jeff sees as the more simplified engineering concepts of electron flow, impedance matching, and optimizing inductance and capacitance. By manipulating their physical geometry to control LCR (inductance, capacitance, and resistance) values, they try to achieve what they believe to be the most ideal relationship between those parameters and, therefore, deliver an optimized electron flow. Jeff goes as far as to state that, within the realm of normal cable design, the LRC characteristics of cables will not have any effect on the frequency response.


As this is the very argument that all the cable flat-Earther’s out there use to support their contention that cables can’t possibly affect the sound, it seriously complicates things, almost to the point of impossibility, when trying to explain how and why interconnect, speaker, digital, and power cables have a demonstrably audible effect on a systems resultant sonic tapestry.


He points out that the waveguide physics model explains very nicely why interconnect, loudspeaker, digital, and power cables do affect sound quality. And further, it can also be used to describe and understand other sonic cable mysteries, like why cables can sound distinctly different after they have been cryogenically treated, or when they are raised off the floor and carpet.


As such, his design goal is to control the interaction between the electromagnetic wave and the conductor, effectively minimizing the phase errors caused by that interaction. Jeff states that physics says that the larger the conductor, the greater the phase error, and that error increases as both the number of conductors increase (assuming the same conductor size), and as the radial speed of the electromagnetic wave within the conductor decreases. Following this theory, the optimum cable would have the smallest or thinnest conductors possible, as a single, solid core conductor per polarity, and should be made of metal with the fastest waveform transmission speed possible.


Jeff stresses that it is not important to understand the math so much as it is to understand the concept of electrical energy flow that the math describes. The energy flow in cables is not electrons through the wire, regardless of the more common analogy of water coursing through a pipe. Instead, the energy is transmitted in the dielectric material (air, Teflon, etc.) between the positive and negative conductors as electromagnetic energy, with the wires acting as waveguides. The math shows that it is the dielectric material that determines the speed of that transmission, so the better the dielectric, the closer the transmission speed is to the speed of light.


Though electromagnetic energy also penetrates into and through the metal conductor material, the radial penetration speed is not a high percentage of the speed of light. Rather, it only ranges from about 3 to 60 meters per second over the frequency range of human hearing. That is exceptionally slow!


Jeff adds, "That secondary energy wave is now an error, or memory, wave. The thicker the conductor, the higher the error, as it takes longer for the energy to penetrate. We interpret (hear) the contribution of this error wave (now combined with the original signal) as more bloated and boomy bass, bright and harsh treble, with the loss of dynamics, poor imaging and soundstage, and a lack of transparency and detail.


Perhaps a useful analogy is a listening room with hard, reflective walls, ceilings, and floors and no acoustic treatment. While we hear the primary sound directly from the speakers, we also hear the reflected sound that bounces off all the hard room surfaces before it arrives at our ears. That second soundwave confuses our brains and degrades the overall sound quality, yielding harsh treble and boomy bass, especially if you’re near a wall.


That secondary or error signal produced by the cable (basically) has the same effect. Any thick metal in the chain, including transformers, most binding posts, RCA / XLR connectors, sockets, wire wound inductors, etc., will magnify these errors. However, as a conductor gets smaller, the penetration time decreases, as does the degree of phase error. The logic behind a ribbon or foil conductor is that it is so thin that the penetration time is greatly reduced, yet it also maintains a large enough overall gauge to keep resistance low.”


For those interested, here is more info from the Silversmith site, with links to a highly technical explanation of the waveguide model and it’s relevance to audio cables:


https://silversmithaudio.com/cable-theory/


tommylion

Showing 7 responses by millercarbon

I had an electrician help me wire my house. Whole new service, new panel, the works. Didn't just do it, helped me do it. Learned a lot. But I am no electrician. Read on to see what I mean.

Building inspector comes out and to me it was like every word out of his mouth just got dumber and dumber. I stood dumbfounded as my electrician nodded and went along.

Afterwards I asked, is it me? Or is he totally full of it? Because this is like a full day's work just to make this moron happy. 

And he said yes. But if we argue he can invent even more and so we will do all his stupid senseless waste of time stuff. 

This then is the life of the electrician.

 

Coincidentally there is a recent review in audio science review in which RCA cables from three distributors, with fairly wide price differences, are compared from both a performance and an auditory perspective. No significant differences were found

What a surprise. ASR is deeply conflicted, and tragically misinformed. Just look at this: 
compared from both a performance and an auditory perspective

What do they mean, "both"? The whole purpose of high end audio is sound quality. The "auditory perspective" IS the only "performance" that matters. How it sounds is how it performs. They are one and the same. The whole point of high end audio is to reproduce the sound of music. Of this they are utterly oblivious. Deep, tragic confusion. Epic. Anyone wants to know exactly how NOT to get good sound, study ASR. The Gold Standard of ineptitude.
I started to watch the video but the first statement in the video: "The square wave and the sine wave are the same thing only with distortion" is complete lunacy. Anyone who knows elementary Fourrier theory knows that, so I couldn’t sallow any more pseudoscience and stopped watching.


Well no, but good job playing the typical forest for the trees blinkered audiophile. You will now proceed to ignore everything I say as well, not even try and understand, just like you did Max. So relax, this is not for you. This is for the open-minded readers capable of thinking for themselves.

The sine wave and the square wave are the same in that they both swing in amplitude. Within the context of the discussion we are concerned with the ringing caused by impedance mismatches. This is most easily seen with the square wave because it jumps in amplitude in one discrete step. This makes it easy to see the reflected wave impulse on the scope. Later on a similar test is run with a music signal. Here it is still easy to see the distortion, but harder for the eye to match it up with the impulse.

Now back to rhg88. You will have no way of knowing just how tiresome it is having to explain stuff- not to people willing to learn, but to people like you for whom this is all one big BSD contest, totally lacking any genuine desire to learn how to build a better system. 

If the day ever comes you open your mind to learning one thing that might register is that it never really happens when you are in argue with everything mode. Open to understanding mode works a lot better.
There’s 3 electrical parameters in poor quality cables that "can" influence the sound.
A combination of Resistance, Inductance and Capacitance, which ’’can" create filters with the output impedance of the source/input impedance of the load

There's a lot more to it than that. Different dielectrics (insulators) have different properties. They all absorb or become charged with signal energy, which is then discharged back into the cable with a delay that can be heard as smearing. This does not happen uniformly across the full range of frequency. Nor does it happen uniformly with regard to amplitude. The dielectric can be thick or thin, or can be air, or any combination of material and air. Every one of these choices affects the resulting sound.

So even just this one seemingly simple decision, which insulator to use, has an impact on the sound. An impact on the sound we can easily hear, but that is in no way reflected in LCR. Just one example.

Another, impedance matching. Regardless of cable LCR if there is an impedance mismatch at either end there will be a reflection back up the wire, where it reaches the beginning and reflects back again. The resulting ringing colors the sound. This is another one that can easily be heard as Townshend F1 are designed to eliminate this, and the resulting neutral clarity of tone is obvious. 

Then there is geometry. Conductor composition. On and on. Some of these do measurably impact LCR, but some do not. Measuring LCR alone is simply not adequate. It is not that LCR is nothing or irrelevant or meaningless. It is simply that it is nowhere near as simple as some would pretend.
Yeah, you are missing the inconvenient fact that the ringing can clearly be seen on the scope. The signal is fast, but not speed of light fast. Nor do electrons travel by the way. Some do but by far the majority of the signal is wave propagation, in which electrons carry the charge but do not need to physically move any more than the people in the stadium need to physically run around to propagate "the wave". Metaphors are never perfect but there are better and worse ones. Ultimately no matter which one you choose it helps if it aligns with the facts. There is ringing. You can see it on the scope. You can hear it if you listen. 

Whatever wire is inside a speaker, what does that have to do with anything? That is as lame as "power travels 500 miles what difference can the last 5 feet make?" Ringing is ringing. Are you saying less isn't better? What are you saying anyway? Besides some internet guys did something on the internet?
To anyone who has working ears

Unfortunately severely limiting your share of readers on the site.
Physicist here.  

I'm buying this.

Not.


See what I mean?
The man himself was here for Chuxpona. We heard him, we heard his cables. They are really good, I would even say exceptionally good for the money. 

As far as his theory or design principles go, well there we have a bit of a problem. Max Townshend has video you can watch showing clearly how impedance mismatches cause a reflection to travel back down the cable. Easy to see on the scope. https://www.youtube.com/watch?v=rUAKE6I3AmM&t=1s 

Also interesting is that what is seen on the scope matches what is heard from different cables. Impedance mismatches do seem to create ringing distortion. This colors instrumental tones and textures, alters characteristic instrumental timbre, and so the less of it the better. 

Still, there is almost certainly more going on.

If you look into speaker cable design you will find a number of them based on similar ribbon construction technology. Each one emphasizes a different aspect of it but the one thing they all seem to have in common is people find they offer a lot of value for the money. So possibly it is the ribbon technology itself that accounts for a lot of it. 

This brings me to the main point I want to make, which is that the key to science isn't what theory or how or what we measure. The key to science is we keep an open mind to the possibility that no matter how good it sounds it may all be bunk.  

Or as the great Richard Feynman once said, "Science is the belief in the ignorance of experts."