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

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.

 

Going out on a limb here and guessing Jeff understands the concept poorly and the math even less. What he wrote is good entertainment though. There was another guy schlogging his own unique and flawed ideas about cables a few years back. He didn't understand the math either though numerous people tried to explain it to him. Spread it on tons of forums. What a mess.

 

As long as there are disciples there will be priests.

Here’s something that says wire is directional. Make sure to use CC setting to get the subtitles and enlarging it would help as well.

 

All the best,
Nonoise

“Going out on a limb here and guessing Jeff understands the concept poorly and the math even less.”
 

“CEO/Designer Jeffrey Smith is a Wyoming native and a graduate of the United States Naval Academy with a Bachelor of Science degree in General Engineering. He also earned a Master of Science Degree, With Distinction, in Defense and Strategic Studies / Weapons of Mass Destruction Studies from Missouri State University and was a National Defense University Countering Weapons of Mass Destruction Fellow. His initial tours in the Navy included assignments in which he studied sound transmission in and worked with the acoustic environments of some of the world's oceans.”

 

Yeah, sounds like the guy has no clue🙄 Seems you sawed off the limb you went out on.

Since a certain someone has expressed interest in what others use for their analyzers, I wonder if he has a Hioki IM-3533 or 3536 LCR Meter to accurately test with. 

I recall a similar person (from ASR) awhile ago who touted his expertise and the analyzer he used but went into radio silence when I pointed out the guy he derided had an analyzer that was multiples of cost and accuracy of the run of the mill unit he used. Just saying.

All the best,
Nonoise

@tommylion ,

 

His Batchelor's level will provide him almost no background in the required material, and his Master's would provide really not a whole lot more.

Look at a Nelson Pass discussion, he talks about specific levels of distortion, what that does, etc. He does not just know the basic theory, he knows the practice and how it translates into the real world.  I don't see Jeffrey Smith saying anything that matters. Throw out some impressive sounding technical terms, never show what happens when you apply all that stuff to his cable, and a real audio system. It will likely have a pretty good L vs C ratio, i.e. L will be low, with correspondingly low C, as would be expected of wide conductors. However, without fixed spacing it will not be consistent.

 

@nonoise ,

What is the value of a $7500 LCR meter versus a $250 LCR meter if you don't know how to use it, or even what the measurements truly mean, or how to apply it? I have lost count of how many times I have seen a cable promoter measure LCR and then calculate characteristic impedance wrong for audio. $250 or $7500 you still get a wrong answer.  Lower cost tools are less accurate and may have restricted frequency range. Do you need to know the LCR of an interconnect cable at 1MHz and to 0.05% accuracy? I know I don't.