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/
Hello all, Here are a couple of peer-reviewed journal papers that may add some useful information to the discussion.(1) http://boson.physics.sc.edu/~kunchur//papers/Audibility-of-cable-pathways--Kunchur.pdf (2) http://boson.physics.sc.edu/~kunchur//papers/Interconnect-cable-measurements--Kunchur.pdf These and other audio related papers are linked to the author's website: http://boson.physics.sc.edu/~kunchur/
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No thread about the most important matter for any system: acoustic and psycho-acoustic... Hundred threads about cables which are only secondary artefact, that matter yes but which is NOTHING compared to the acoustic impact or even to the vibrations control impact or to the noise floor house problem...
People buy panels and bass traps, costly one, and call that problem solved, then debate about cables till their death... 😊😊😊😊😊
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I’ll preface this by saying that I haven’t read the entire thread so if I’m rehashing stuff fell free to ignore me. That said, I was an engineer for 35+ years. My specialty was EM theory, mainly various types of antennas but also a lot of work on waveguide components. The frequencies involved in audio are much too low and the lengths of cables are much too short for waveguide theory to be of any use. At 20 KHz the wavelength in the cable is on the order of miles. Until the length of the cable is an appreciable fraction of a wavelength, waveguide theory has nothing to say. I don’t care what degrees this guy has, his explanations are hogwash. |
And a minor in weapons of mass distraction? |
Bachelor's Degree if you wish to be pedantic. Degree of Bachelor of XXX if used the way you did. Highest English mark in final year in a High School of 1400 students but thank you for asking. I still make too many spelling mistakes. Computers can fix most of that. Unfortunately they can't fix people. |
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.
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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, |
“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. |
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. |
So this Greg weaver guy thinks that "wave propagation" trumps resistance and capacitance and he also believes that digital cables will sound better using "wave propagation" as the design philosophy. Makes my head want to explode. This guy is a master advertising writer, heck if I was selling cables, power cords or anything in that realm and wanted to snooker unsuspecting customers, I’d hire him in a New York minute. BillWojo |
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.
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It is so reassuring to know that the venerable and ever-righteous electricians are willing to take time out of their busy measurements and calculations to instruct we Dionysians on our hearing! I'm sure all thinking audiophiles will agree that we do sometimes listen to things that we shouldn't--image, depth, soundstage, music, etc.--and then act like jerks because the electricians can't hear anything they can't measure. The work of the electricians is indispensable to anyone participating in the audio marketplace and we all need to appreciate their endeavors while we wait for them to find the square root of two. |
So, either I buy into skin effect, waveguide, blah blah blah, or... I believe this is caused by gear and ears being more sensitive than the pure math shows. The third column is the psychological aspect of expectation. That is a whole bundle of interesting and confusing stuff. |
djones514 already expanded on my concern with equating a square wave to a sine wave in the video. The square wave and sine wave are not the same thing the square wave simulates all audio frequencies and MORE, the and more is infinite bandwidth. The test shown in that video is not band limited to audio frequencies The refections shown are above 50kHz. Using a square wave as a test signal produces harmonics with frequency content well beyond audible frequencies, As djones514 already pointed out, the refections shown in the video are above audible frequencies. maybe your cat and dog may be able to hear the difference, but not you. from wikipedia:
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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. OK, i would not state it that way. But...., step back. A distortion is a "change or difference in an electrical signal". Well, its a big difference no doubt, but i think that’s his point. Maybe a stretch, but valid/true. Just sayin’ |
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FYI, the technical definition of impedance is more than resistance. :) And yes, in theory, the math says cables should barely matter... but experience has shown me that frequency response does change noticeably with cables. So, either I buy into skin effect, waveguide, blah blah blah, or... I believe this is caused by gear and ears being more sensitive than the pure math shows. Given those two choices, I pick the latter, simpler version. |
Most of what i hear comes not from cables changes or gear changes....I am no more like deluded consumers or deluded sellers warring with each other... Most of what i hear comes from the SPEAKER-ROOM interaction controlled or not... My experience contradict most audio thread where people weight the merit of different piece of gear, ravished by the magical virtue of one chosen piece gear.... Silent about the room.... |
holmz308 posts Cable Pathways Between Audio Components Can Affect Perceived Sound QualityAuthor: Kunchur, Milind N. Affiliation: University of South Carolina, Columbia, SC 29208, U.S.A. JAES Volume 69 Issue 6 pp. 398-409; June 2021 Publication Date: June 1, 2021 Here is the abstract: The arena of highest fidelity in music reproduction, sometimes referred to as high-end audio, has many controversial claims and contentious issues. One such controversy is whether the cables and topology used to interlink components together make an audible difference. There seems to be a disparity between anecdotal experiences reported by audiophiles and published formal scientific research, as to what are the minimal changes in system configuration that can be audibly distinguished. With the motivation of bridging this divide—which may originate from differences in instrumentation and subject-listening conditions used by the two groups—this work utilized a high-performance audio system and an extended-duration listening protocol that more closely resembles audiophile auditioning conditions. With these measures, the present work was able to prove through direct psychoacoustic testing that two different analog-interconnect pathways can be audibly distinguished. A PDF of article can be obtained here: pdf file. (from the author's own web site: http://boson.physics.sc.edu/~kunchur//papers/Audibility-of-cable-pathways--Kunchur.pdf I plan to read it more carefully when I have time, to make sense of the so-called psychoacoustic results that are included in Table I of the article. |
It isn't news that resistance affects frequency response of the speaker which might be audible. These claims of waveguide and quantum whatever and an esoteric dielectric can make huge differences in cables with the same basic LCR is where I begin to have questions. That is an excellent read by Benchmark it shows how little the cable affects the total resistance. |
What I hear is minute changes in frequency response. I'd say mostly correct. One of the better explanations on how resistance affects frequency... https://benchmarkmedia.com/blogs/application_notes/audio-myth-damping-factor-isnt-much-of-a-factor |
I’m afraid that while I do believe cables can sound differently, and have some testing with non-audiophiles to prove it, ALL of it, absolutely ALL of it I’ve ever heard is explained more simply by changes in frequency response than anything else. To my knowledge, MIT capitalized on this more than anyone I know adding capacitors and inductors to do just this. My belief, that’s opinion to the rest of you, is that equipment and speakers are more susceptible to minute impedance changes than we’d like to believe, and that all these cables do, if they do anything, is add enough capacitance or inductance, or maybe even less or more shielding, that it becomes audible. I’ve read a lot of these wave guide and skin effect theories, all of which get debunked pretty handily. These oh so complex theories fail Occam’s Razor. Nor do I believe they’d be audible. What I hear is minute changes in frequency response. What I see is a lot of audiophiles claiming increased resolution, clarity, imaging. Yeah, even cables which improve imaging is best, and simply, explained by changes in frequency response than anything else, but off we go chasing exotic explanations and materials. Well, by all means go ahead, don’t let me stop you. Oh, and few audiophiles I know of actually want neutral. They chase the next flavor of sound like the next famous condiment. I'm not saying it's bad, but I do think that chasing flavors like this end up chasing sound which is far from the recording. It's your audio sandwich though, please make yourself happy. |
If you believe that wire has capacitive and inductive properties… and different wires have different capacitive and inductive qualities (which can instantly be show on even a cheap multimeter)……. THEN…. All the science you need re. Analog cables is two reactance formulas. Exactly. And this is just the beginning of all the variables (skin effects, dielectrics, etc.) that can affect sound. |
35 years ago Alex Gibson of FMS cables used the latest greatest Mac to run tests on his cables. A few were rise time and overshoot and echo return and reflection partially because a digital cable could be to short or to long for best measurement and best sound. Alex Gibson was way ahead of his time. Tom |
ASR? The guy admits he doesn't even listen, only looks at measurements. What is being reviewed? The distortion figures etc. are being provided but none of this is being related to the actual sound. The measurementalists, measurebators and others of that ilk may find it interesting, informative or even useful, though I can't see how. I think his 'contribution' to the furtherment of audio is misguided, that is if he is indeed interested in actually contributing. What is taking place IMO is a great disservice as evidenced by the poster who felt reassured after reading the !@#$% review and is happy with his cheap amazon basics cables. |
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 Do you have link to ^that^ AES study? |
Most people think the sound come FROM their beloved chosen gear... When they dont like the sound they replace the gear and called that an upgrade... Some measure the gear and call that "science", anything not measurable is "magic"... These two different kind of people are deluded, some buy cables to upgrade and others bash them....There is no deep difference here ,they own their own blinders anyway and exist like foe exist for the sake and by the virtual existence of the other neighbouring foe.... I am afraid the truth is too complex for simple mind and too simple for complicated unclear mind : The sound we listen to come MOSTLY from speakers/room/ears interaction...Not FROM the gear directly even if the gear play his own impact on the sound quality.... How do you measure that? No way.... It is a dynamical CIRCUIT in hundredth of seconds between the speakers--->the room-->`the ears--> add a change here in the room treatment or a new Helmholtz resonator for example and listen another time... It is a listening experiment in a CYCLE of experiments.....Even a single straw at the right place with the right diameter may have an effect comparable to an upgrade.... Because a tone is NOT a playing note or chord, nor the timbre could be reduced to a spectrum, you cannot replace ears with a measuring apparatus....And you cannot replace acoustic laws and psycho-acoustic laws with a piece of new gear or a new cable to reach High quality sound.... Is it not simple to understand? |
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. |
The AES paper doesn't tell you anything other than RCA and XLR, unbalanced and balanced can sound different. It didn't compare apples to apples. The square wave and sine wave are not the same thing the square wave simulates all audio frequencies and MORE, the and more is infinite bandwidth. The test shown in that video is not band limited to audio frequencies The refections shown are above 50kHz. |
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 https://secure.aes.org/forum/pubs/journal/?ID=979 That's funny AES did a study and found the opposite. I would trust AES over ASR any day of the week. |
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. |
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. https://www.audiosciencereview.com/forum/index.php?threads/battle-of-rca-cables-mogami-amazon-monopr... Of course we now know that we need "paranormal instrumentation", based on wave guide science, to tell the difference. |
According to millercarbon, "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" 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. |
Hear is a science lesson and a couple of hour stream of consciousness from a audiophile and 40 year engineer with Belden.Thanks for posting this link @theaudiotweak . Enjoyed it immensely, and should be required watching for everyone. Can't believe it only has 1000 views. |
There's a lot more to it than that. Different dielectrics (insulators) have different properties. I wasn't going there but thumbs up. Anyone who doubts read a datasheet on capacitors and all the characteristics of them; most critically to us (IMO) dialectic absorption. The video(s) i linked get into the why - its the basically physics of electromagnetic propagation, which is in the wave, in the dialectric, merely guided by the wires. While the effect at low frequencies may be smallish, I strongly believe that at the very least it is best to use twisted pair (tight waveguide) with a dialectric that is linear - typically both a plastic film such as polypropylene, polystyrene, teflon, or mylar, and if possible low density (e.g.: expanded foam). What do you know, hgih frequency radio communications demands the same thing. G |
With the title being “Science can explain…”, it is hard to believe that these cables can sound different when there is no scientific proof that the signal going through them has any measured difference. If they are shown to be able to identified subjectively as different, then we would be in a different place and could at least know that they are different. |
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There’s 3 electrical parameters in poor quality cables that "can" influence the sound. 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. |
Different Analog Cables absolutely can sound different. The following is my best attempt at an argument to lend to its proof. I think this is as straightforward as I can offer… I avoided posting this for 20 years… anyway…here goes. If you believe that wire has capacitive and inductive properties… and different wires have different capacitive and inductive qualities (which can instantly be show on even a cheap multimeter)……. THEN…. All the science you need re. Analog cables is two reactance formulas. Reactance is essentially a measure of “non-linear”resistance… i.e. resistance which VARIES with frequency (analog musical signals contain many frequencies 😉). for inductance…. Inductive Reactance Value= angular frequency for capitance …. Capacitive Reactance Value= 1 divided by angular frequency Note: angular frequency IS ITSELF a formula…which contains frequency as a variable. Used here for simplicity and the fact I don’t know how to get Greek symbols on this keyboard. These values are used to design circuits and wires and….different values will yield different results…and…different SOUND. This is second semester electronics engineering….not some exotic quantum theory. Therefore what is conveyed by a cable in the analog realm is absolutely affected by its electrical properties…which are a product of its materials and construction. I can only speculate that those who refuse to believe it either have an agenda, lack actual experience, or have an under-resolving system. Now….digital cables …that is an ENTIRELY different discussion. 😬 |
