My bad english, no i did not ask proof that cables are not directional perse ( i said "so, where is the definitive proof it is snake oil, or not?"). The OP stated ( in my opinion quite categorical) it was NOT directional, so i asked for proof. The video is not a valid proof for me. And if i understand your point correctly, it cannot be, nor is it adding any value if so far nobody has been able to proof it.
A little background on me: Some 45 years ago i started producing loudspeakers and in that time the notion surfaced that a cable (copper conductor) was not "just a piece of wire", it could influence the perceived sound. In that period Jean Hiraga and others started L'Audiophile , and during several Festival du Son shows in Paris and shows in Belgium and Netherlands we had some good discussion amongst others on the subject with Jean, Michel Reverchon (founder of Goldmund) and others.
As we did use quite some length of wires in the loudspeakers, we tested of course. To cut a long story short, it came down to the quality of the copper with the feedback from the copper wire manufacturer (pristine versus recycled copper) and to a lesser extend the diameter of the conductor becoause of skin-effect. With pristine quality copper there was no directionality noticeable. The thickness only an effect on the high end, thicker wire a slightly more rounded top-end. (At that time silver-clad copper was used to get the thop end more airy, but was another rabbit hole, so i did not use that.
Even with pristine copper the way the conductor is connected (soldering, clamping etc )to the connector (driver-unit, spade, bananaplug) is a sure source of problems, as well as the connector (spade, bananaplug etc) itself. In the publications of L'Audiophile this topic was quite well covered, as Jean had access via Sony to some serious test equipment we could only dream of.
Nowadays copper quality in loudspeaker cabling normally is OFC and 99.999999 or so pure, so that should not be a issue anymore. I am not so sure about the connectors though.
The lesser quality copper indeed had some directional effect (it sounded less distorted in one direction versus the other). The insulation around the conductor also had some influence, then attributed to static charge buildup in the insulator. In that time the then well known Lucas loudspeaker cable came about with a grey insulation that could not build up static charge.
Mind you i am talking about loudspeaker cabling. Signal cables with several possible geometrical constructions is a more complicated matter, and i stayed well away from that.
Several years later i stepped out the HiFi business to pick up my original profession as naval architect. I found the HiFi business going in a wrong direction where brand image became way more important than sheer sonic qualities and enjoying music. (Around that time the loudness war -as we know it now- started).
During the recent covid-19 period i sort of got interested in the state of things in HiFi again, and was quite shocked by the nonsense about cabling with stellar prices to boot. Simply way over the top.
Jan,
Actually there is skin effect at audio frequencies. It is not a binary thing, however even at 40,000 hertz the depth is so small it is not significant except for those who have hearing ranges well beyond human. 😉
I also deliberately used a torch to discolor some copper wire and then measured for diode/skin effects. None were detected. But this was limited to about a 140 dB dynamic range. I can’t quite ever get to the practical limit of 195 dB. (That covers best expected threshold of hearing to complete atmospheric modulation. )
Actually there is skin effect at audio frequencies. It is not a binary thing, however even at 40,000 hertz the depth is so small it is not significant except for those who have hearing ranges well beyond human. 😉
I also deliberately used a torch to discolor some copper wire and then measured for diode/skin effects. None were detected. But this was limited to about a 140 dB dynamic range. I can’t quite ever get to the practical limit of 195 dB. (That covers best expected threshold of hearing to complete atmospheric modulation. )
Sorry Ed, I deleted my post before reading yours, I get so fedup trying to explain things to those who are too lazy to educate themselves. I'm getting too old I guess.
Jan
Jan
There is a peach inside the sun after all… I’m sorry, but there is no proof of cables being directional. One may stick to belief, but any advocacy is like preaching. And of course preachers know there always are devote believers.
Jan,
Age is a relative thing. It improves both wine and one’s scope of understanding!
I did recently get turned down for a lunch date. She thought I was too young! (70 is the next birthday celebration.) (Yes she was still breathing and almost 15 years younger than me. )
Age is a relative thing. It improves both wine and one’s scope of understanding!
I did recently get turned down for a lunch date. She thought I was too young! (70 is the next birthday celebration.) (Yes she was still breathing and almost 15 years younger than me. )
I see no harm in cables marked with direction indicators. At worst it doesn’t matter and at best it saves time for OCD sufferers. 😌
I can reason why a cable may exhibit directional effects in a particular set-up, but not optimum in a pre-determined direction, universally.
8 nines copper, where do you buy that?
Had a customer who wanted to use 7 nines dead soft copper for a solenoid at 4.5Kelvin, wanted to take advantage of the three orders of conductivity improvement at liquid helium temperatures. I pointed out that the simple process of winding the coil will kill the mean free path increase by work hardening even though bend radius was 2 inches and the wire was roughly 24 awg.., so the coil will dissipate more than they can stand... so they went with niobium titanium instead and took a small hit on nucleus cross section.
Many of your anecdotal statements come with no proof, such as directional distortion and static charge buildup. If it existed as an effect on signal carrying wires, my work life would be far more complicated. As it is, just dealing with NEC requirements with large machines is difficult enough as the typical AHJ has no experience with scientific machines, just AC power distribution.
Your mention of connection integrity is certainly agreed upon.
The names you mentioned, I'm afraid I do not recognize any of them, I assume they are important people. You must have had fun discussing topics with them..
John
Are you sure it was that and not that she had good taste??
Had a spill a month ago, tripped over a dog in the dark reaching for the light switch (on the wall opposite the door, who designed that??) Luckily, the bathroom vanity granite edge broke my fall by gently attacking my left orbital, knocked out.
Kids said I was speaking incoherently for about half an hour.
A co-worker asked me...how could they tell?
john
A wise man recently said, the final stage of a theory is belief. But the final stage of experience is knowledge.
Matthew Polk's US patent 4,177,431 (Dec 1979) discusses this very idea. Column 1 lines 5 thru 55.
His solution is to intentionally make the cable directional (asymmetric) by attaching a series RC terminator network (zobel) at one end of the cable but not at the other. Specifically at the loudspeaker end. See column 4 line 1 for preferred values of R and C.
The zobel protects the amp should the speaker unload impedance wise below unity gain of the amp. Low inductance cables are high capacitance.
John
That's nonsense. Gene believes nothing of the kind and conducts extensive testing of cables over a very wide frequency range. Well beyond the audio range. And with high-end spectrum analyzers.
You either didn't really watch the video I referenced in Post #38 or didn't understand it.
You did not understand my point.
He is relying on a measurement tool that excites the load at a single frequency. Yes, it is swept, but the signal is still just a single frequency.
A voice coil's impedance is dependent on the position, velocity, and acceleration within the gap. For example, it's impedance at 1 khz is a time dependent entity when the coil is moving within the gap as a result of drive at another frequency, say 50 hz.
The test equipment to measure this is not SOTA spectrum analyzers, they cannot do this.
I do not blame Gene for not understanding this, nor anybody else... it is conceptually well beyond most.
It is, however, a subset of what I do for a living.
Gene's not a bad guy, we had lots of back and forth discussions back when he first started AH. If you peruse his site, you will find him quoting me on cable stuff. I backed out of his site when my ability to post graphs and pictures in support of a biwire analysis was curtailed. My technical explanations did not fit his schtick, and suddenly my stored library of graphs and such exceeded my allowance by a factor of ten.. I do not know if he made the decision to censor me, or if it was a site bug, or whatever. It does not matter. It is his site, and his living so I cannot fault him.
john
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I was sure I made the explanation really simple, but clearly I did not. I will try to keep this as simple as possible..
To measure impedance across a wide band of frequencies, the instrument does not throw white noise at the system. It starts at one frequency, and changes that frequency until it reaches the other end of the band.
It has to do this slowly, as slewing the frequency too fast can introduce artifacts that are caused by the method, not the device under test.
An HP meter, for example (agilent nowadays) pushes a sine voltage into the load, and measures the current the load draws. The current in phase with the voltage is considered the resistive portion of the load, the current 90 degrees out of phase is considered the reactive component. For accuracy, the machine has to remain at a specific frequency until the system has settled down, and the machine integrates the measurement. The tradeoff is in how long to remain at a frequency vs how accurate one needs the measurement. The designers of analyzers take this tradeoff into consideration when they design their instruments.
The HP machines do not have the ability to discern eddy current losses (which are actually at twice the drive frequency) from IR losses. Nor can it distinguish inductive exclusion caused by eddy reaction from system inductance of the stored field.
So, in response to your first statement, no I do not have any problem with understanding this stuff. I do have problems with the limitations of current SOTA equipment however, as I many times am called upon to do measurements (and other neat stuff) that have never been done before. That I must admit, is really really cool, and the reason I've not yet retired...
John
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Yeah, I grasp your point now and I guess you do understand it. Although the wording in some of your earlier posts raised some doubts about that.
So, let's just make it clear to everyone. In a typical frequency response measurement of a device, it could be a cable or an amplifier or anything else, an input signal is applied as a sweep usually from a low frequency to a high one over a period of several seconds, and the resulting output amplitude is plotted correspondingly.
And that type of measurement has been the standard bedrock that has satisfied essentially everyone in the past to predict the performance of a device when used to reproduce music. Certainly, people like Floyd Toole and others with similar backgrounds have found it to be extremely useful in predicting audio performance.
But you appear to now question whether those measurements are a valid and useful tool at all, because there may be some small eddy current losses that aren't accounted for.
So, let's just make it clear to everyone. In a typical frequency response measurement of a device, it could be a cable or an amplifier or anything else, an input signal is applied as a sweep usually from a low frequency to a high one over a period of several seconds, and the resulting output amplitude is plotted correspondingly.
And that type of measurement has been the standard bedrock that has satisfied essentially everyone in the past to predict the performance of a device when used to reproduce music. Certainly, people like Floyd Toole and others with similar backgrounds have found it to be extremely useful in predicting audio performance.
But you appear to now question whether those measurements are a valid and useful tool at all, because there may be some small eddy current losses that aren't accounted for.
I assumed it was just an issue with wording..no problem..
My point on eddy current losses was just one such example where a very good instrument like an HP inductance meter cannot provide details. Another is the measurement of an inductor, where proximity effect causes the current centroid to push to the inside edge of the wire, another twice frequency effect.
People such as Toole are using the equipment and techniques at their disposal to advance everybody's understandings, and they are good at that. Most of the problem is the limitations of their tools, but some of the problem is the state of current knowledge. Things I learn from my work will help that knowledge pool in the long run.
It is quite unfortunate that in the engineering discipline, magnetics, E/M theory, EMI, as well as motion control are sold short. I find that I am constantly correcting inaccurate understandings taught in degreed programs.
The fun part for me is, I am tossed into solving multidisciplinary problems that resist normal investigations, so I learn stuff from some very very high level scientists, physicists, chemists, technicians, and engineers. And I am paid to have that much fun!!
John
Given the choice between believing in the lifelong research of Floyd Toole, who earned a PhD in Electrical Engineering from the Imperial College in London, and your self-proclaimed experience in the field of audio reproduction I will go with Toole every time.
I also find it hard to believe you are constantly correcting misunderstandings taught in degreed programs. If true, that would reflect a very sorry state of affairs for our current universities, and I don't for a minute believe it.