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 8 responses by noske

I think its imperative that the theoretical nature of the thing is well understood.

That he eschews {avoids} inductance, capacitance, resistance and impedance "dances" in favour of wave model is troubling.

"his designs are based solely upon the physics model of electricity as electromagnetic wave energy instead of electron flow".

Now, do any electrical engineers have an issue with this? I’m not, but since when has electricity been modelled on electron flow anyway? Isn’t he finding a distinction that doesn’t exist? Is there a straw man lurking around in the shadows?

Edit - and having waded through the words a couple more times I actually fail to find anything new.  Isn't much of what he is saying standard, but that he throws in things to make it appear as though he has a novel twist, like the maths don't matter as much as what the maths means (not a direct quote but something like that, which to me is all quite odd).
@akg_ca

I don’t think this is about whether cables matter or not - lets agree that they do. Non issue.

What this is about (for me, anyway) is that when the protagonist quoted above says that cables matter, they seem to be appealing to some higher power for inspiration. This does nobody any favours, and forum moderators must go all giddy.

Always a good motto - if you are telling the truth, why is there any need to lie (or embellish etc).

I am so happy to be corrected as I'm still trying to make sense of this, but despite him "eschewing" traditional theoretical models, isn't it exactly that upon which he relies, despite his protests?

Like, gee, even I know about the dielectric aspect, and I know nothing compared to the many erudite enthusiasts, physicists and electrical engineers on this forum.

I can't see where he actually says what is underlying his wave "philosophy" that has nothing to do with physics etc.  Could it have anything to do with protons or photons or something like that, perhaps?  Just guessing from trying to remember from what I have read from traditional designers who are unashamed of their impressive scientific  credentials.
The type of cable and the manufacturer doesn't matter, my point is that from my experience, no matter what the technology, it's a hit or miss with cables, and if you're lucky, and all of the hidden variables happen to align... based on reviews, or recommendations, and within my ability to afford the particular cable.


I suppose you can rely on recommendations and "no matter what the technology" (whatever that actually means) and cross ya fingers for a bit of luck for the stars to align.  I consider such an approach to be not financially prudent and emotionally draining and depressing.

I say get the foundations correct first, the known theory must be taken advantage of and exploited.  Then, line up the contenders and select.

Should another cable which ignores ("ëschews") known theory sound better than any of those in my prior paragraph, all kudos to whoever designed it. 

However I would wager that it is nevertheless mostly consistent with known theory, whether the designer admits it or not.  There is obviously some marketing advantage to be gained by appealing to something "öther". 

Gotta find an edge.  Credible designers are fully transparent, and from an intellectual property aspect this can be a tricky balancing act.  So, what they can claim is that the edge can't be measured.  As if.  Run away.


@djones51 when science is used as in the articles cited in the OP to promote cable sales and sound difference it’s okay to call BS when the underlying principles in those articles prove no such thing. Buy what you want but don’t deride science then use it.


I think that was what I’d have liked (or was trying) to say in my convoluted rants, but was slightly unsure of myself. Thankyou.

No credible scientist would ever say that the science is settled on any number of issues.

But neither would they distort and misrepresent known and agreed on principles - to do so revokes any and all credibility. They have a lot to answer for on a wider and quite serious ethical level.
Why not apply it to audio cable design, if it produces desirable results…? Apparently it has, at least for some.


Red paint applied to cars makes them go faster. Apparently it does, for some - ask any traffic cop.
A clue: science is not an industrial planified theoretical and experimental centralized project


Yeah, people should stop saying that about science all the time, I agree.

Where's that confounded vodka.  Dingo must have taken it.
When the argument is presented that “science says it isn’t so”, it’s a very limited outlook. The phrase should be “our current scientific knowledge suggests that it shouldn’t be possible”.


I'm not actually sure where “science says it isn’t so” is actually put forward in the context of this thread ( the title is "science that explains why we hear differences in cables").

In the meantime, my own hearing and perceptions will never catch up with the known science/technology that is currently available.  I have a long way to go before I am sated, or needing to engage in pursuing possible off-the-radar holy grail possibilities.

I have no qualms should that be considered a limited outlook.  The DC comic character Superman may find our humble scientific knowledge rather quaint, however I can't recall him ever even listening to music.  I reckon us humans have a few tricks to show those aliens.