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Where's the beef
Skin effect, fermi velocity, strand jumping, oxygen molecules, grain boundries, are all hypothetical explanations for supposed electrical distortions but the distortions ultimately must show up as waveform distortions or they don't exist. Where are the impulse tests, tone burst tests, square wave tests, and input output linearity tests. This is also ancient technology of 40, 50, even 60 years ago. Today we should expect segments of complex musical waveforms captured and computer analyzed to breakdown where, how much and to what degree these distortions manifest. But beyond telling me that this wire with x number of strands has such and such an inductance per foot and therefore so many tenths of a decibel difference at 20 kzh than the other with a different number of strands and as for the difference in group delay, that is also all straightforward as the frequency response also must include the phase as well as the amplitude response I feel I am getting nothing from so called cutting edge technology. At NASA, these guys would be fired if that were the best they could come up with. All undergrad ee material. So where are all those clever guys with all that high powered equipment and that fancy mathematical analysis? And that's just the electrical engineering end of it. After that comes the psychoacoustics where the DBTs would have to tell us if any of this stuff is even audible. So where's the beef?
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[QUOTE=pctower][QUOTE=mtrycraft]Well, Davis had a critical review before publishing in a Journal.
So why did Chuck ask for discussion if there is absolutely nothing to question?
He asked if these were discussed before. Perhaps questioning the author is in order? He does have an email, not in the Journal article but can be found, and am sure he would respond.
I've got a serious question for you. Do you universally accept as reliable any test where the results confirm your beliefs?
To the day until I am convinced otherwise. No, you are wrong, I can be convinced by better data. I may be wrong, from time to time. I still have a number of unused fingers left :)
Do you see any value in questioning test results that seem to confirm mainstream beliefs?
Depends on the tests and beliefs being confirmed, or not.
While we are at it, do you claim to be objective on the subject of cables?
Yes. I try to be objective on many things.
How would I know. Chuck asked for some discussion.
Sounded like you asked the question and had a known answer to it. Ask away. I have not seen any evidence to indicate that is would, in the audio band at least.
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You've got that bass ackwards.
You think? Could be but then, evidence is best, not speculated.
Perhaps you listen to test tones,
When necessary, I do. It is very sensitive to identify small differences.
but I think it is fair to say that most folks enjoy listening to music
Are you speculating again something about me? Please don't.
It is your camp that begins with the assumption that there will be no difference with tests on simplistic wave forms vs. that which is used in the real world.
But you must have evidence to support your contensions.
The burden of proof is yours to substantiate that assumption. History is not on your side as the value of the time domain has been proven over and over again.
How so. Be very specific.
Do you recall how worthless THD measurements were rendered once TIM was established?
Actually, TIM is unimportant, really. Overblown by some over active imaginations of some.
Too bad the Doug Self amplifier institue has changed web sites again. But then, you have no idea who he is, what does it matter? Do an AES Journal search.
[b]Do you recall how worthless most specifications were on the "perfect sound forever" digital players prior to the understanding of jitter?/b]
Please, you have no idea of digital audio history in the real world. Don't repeat voodoo bs and make something of it that wasn't/ Don't confuse marketing hype and engineering know how, or invent a meaning for things you don't know or the onse who try to interpret it.
How about perfect sound forever meaning that the digital data will be reproduced the millionth times as well as the 1st time? No wear as in vinyl records? Let you imagination run wild what 'perfect sound forever' really implies? After all, that is all it is, you imagined meaning.
Why not ask the one who wrote that what he/she meant? Don't speculate about his implication as that is all you are doing.
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What I am hypothesizing is the change in energy storage, not something as simple as group delays..
How will that manifest itself?
Where that stands now? Glad you asked..I am wrestling with my model, and how it stands w/r to superposition. As in, does my model break down in regard to multiple signals each at different skin values...can the resultant be equally described by the sum of the signals, or does my slew rate model break down...still lots of work to do before I can really test it..
Cheers, John
Well, I am still young, just don't quit on me :) I am curious myself:)
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Quote:
Originally Posted by Chuck
I've measured 2dB at 14k, but can you point to ANY other tests of ANY kind that that show greater problems in typical wire configurations? I'm not aware of any, so if they exist I'd appreciate a few links.
But it is not a mystery why this happened, right? The speaker load at that frequency is 1/2 ohm, close to the wire impedance there, no? Close enough to give this drop. And, this is just what physics would predict when you have similar loads, power will be similarly divided.
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I agree, the early CD players sounded dreadful. I attribute that to the awful D/A converters. I was not able to find one I liked until around 1989 when I bought a 20 bit Denon unit which I still use. Two years later, a single bit JVC unit I bought sounded almost identical with just a slightly attenuated high end and none of the barely perceptable metalic sound of the Denon on some discs. Later units have pretty much sounded the same and except for the "audiophile" units which fiddle with the frequency response to "blow away the competition" they all sound pretty much the same to me by now. I don't think digital jitter played any role in the sound then or now.
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HI guys...
Chuck""If there are some undiscovered things taking place in some speaker wire then somehow nobody has ever managed to expose it in any measurement or controlled test, so nobody other than Jneutron is going to waste their time chasing ghosts. With respect to Jneutron, it's a dirty job, but apparently someone has to do it, and he seems to be the right man for the job. ""
You got that right...there is a very, very large possibility that I am chasing ghosts..That has been a possibility I live with all along..But for me, it is not the end result, it's the voyage..because I do not derive income from this stuff, I consider it more as intellectual stimulation, really fun things to theorize and test. As I work it, I derive a more intuitive, gut level understanding of e/m field theory... not like my friend, who is capable of doing anything he wishes (and I don't understand) with Maxwell's equations. But when I present him possibilities he cannot discount using Maxwell...now that is fun.
Chuck: ""Jneutron and I both DO measure such things at times, or at lest we try, but most technical people have better sense.""
Agreed...hee hee...
Asked what current SOTA and understanding of skin effect with wires, I can only fall back on proven, tried and true technology...nothing has been seen.. my slant is, perhaps it wasn't looked for properly.."properly" being an undefined test regime I look for.. The MLS system is certainly excellent, and to prove my point, I must show how MLS is unable to see what I hypothesize..So far, I cannot...may never, but like I said, I'm havin fun.
What I am hypothesizing is the change in energy storage, not something as simple as group delays..
Mtry: ""How will that manifest itself?""
My first guess is a time shifting of a high frequency signal as a result of a low frequency signal being added. So, I first null a hf signal out...then null out a lf signal...if what I hypothesize occurs, the sum signal in the wire will not null out with the sum of the nulls.. That of course, would contradict superposition, the theory that the wire carries each signal linearly, and additively. One of my slants to my thinking is that the load resistors to date are not zero inductance, nor zero b dot setups, so accurate measurement of the voltage/current phase is lacking.
Where that stands now? Glad you asked..I am wrestling with my model, and how it stands w/r to superposition. As in, does my model break down in regard to multiple signals each at different skin values...can the resultant be equally described by the sum of the signals, or does my slew rate model break down...still lots of work to do before I can really test it..
Mtry: ""Well, I am still young, just don't quit on me I am curious myself""
Hey...I'm (relatively) young...at least, you recognize the time scale I'm workin at.. It'll be a while..Right now, still unpacking.
Cheers, John
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Quote:
Originally Posted by mtrycraft
But it is not a mystery why this happened, right? The speaker load at that frequency is 1/2 ohm, close to the wire impedance there, no? Close enough to give this drop. And, this is just what physics would predict when you have similar loads, power will be similarly divided.
Correct. An almost trivial analysis of the circuit is sufficient to understand what's happening in this particular case. Even so, I've not seen anyone else show such a large "speaker wire effect" under ANY circumstances. Have you?
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Quote:
Originally Posted by Chuck
My take is that you are grossly over-reacting in a highly emotional and illogical way, and I have no interest in that type of discussion. As a result I've asked Chris (our moderator) to comment, and until I see some change I intend to try to improve your comfort level by adding you to my blocked-posters list. Perhaps you could do me the courtesy of doing the same?
We can easily unblock at some time in the future if there is any reason to believe that we can have an enjoyable conversation without you getting upset over something that doesn't amount to a hill of beans. In the interest of peace and harmony on the forum let's both do Chris a favor and ignore each other.
Thanks.
Presumably you won't even see this, but I have no interest in blocking anyone, including you; nor do I have any interest in "wining" back unblocked status from anyone, including you.
You can run crying to the moderator if you want, but you must have very thin skin indeed.
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It's about time the engineering pros take a much harder and in depth look at the whole question meaning accuracy of reproduction of real waveforms using computerized analysis seeking non linear distortions and DBTs to back up their findings. In 1984 this might have been a little new. In 2004 it's kindergarten.
Well, he didn't write it in 2004, did he? What is there to show about wires anyhow that is new?
DBT what? Measurements?
Maybe you might be interested in doing all this fancy measurements for such an article?
However, we've been there, done that a million times too so it's rather boring to read it again.
Only boring to the ones who has seen these a few times, not the new people that are new in audio or here.
After all, isn't 2+2 boring? Not to the new kids first exposed it is not.
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Again, I'm asking whether conducting a test under similar conditions, but measuring distortion characteristics of the waveform, including temporal distortion, could possibly have yeilded different results?
Didn't you follow the posts at AA about cable distortion measurements by Curl and Eddy's friend overseas who couldn't measure anything down to -150dB,re 30mV
When will it be enough? -200dB?
Stated another way, is it possible to extrapolate from his tests that measurement of waveform distortion would show nothing of use that was not shown in his test? I think what you are saying is that there is no need to measure waveform distortion. Somehow, though, that doesn't make intuitive sense to me.
When amps have distortion in the 3rd and 4th decimal place and speakers have it 2 or 3 orders higher and the audibility of distortion has been shown, what is there to measure in wire? Besides, as above, there is nothiong to -150dB, limit of the testing equipment of today.
What do I think they overlooked? Possibly waveform distortion.
While that is interesting academically speaking that may already been done at IEEE, who knows, why would anyone be concerned? Why would anyone be interested in looking for it? What reason?
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Quote:
Originally Posted by Chuck
Correct. An almost trivial analysis of the circuit is sufficient to understand what's happening in this particular case. Even so, I've not seen anyone else show such a large "speaker wire effect" under ANY circumstances. Have you?
Nope, not under those circumstances :) That is extreme.
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unless you are an engineer, it is impossible to predict in advance how the cable will affect the sound and if it has any audible effect at all, what creates an improvement (meaning flatter overall frequency response) in one system may cause a deterioration in another.
Now that I reviewed that paper fot the umpteenth time, Davis did plot two system reactions to cable, amp and speaker together and separately. Figures 9 &10 is one speaker load, fig 11 is another. About .4dB difference between the best cable of the 12 and the worst at 20kHz foe speaker A and .2dB for speaker B, although he used only 4 cables there. Hardly needs further speculations there.
Similar for the amp, fig 12.
Figs 13-17 measured total system response. .75dB or less at 20kHz.
There were NO DBTs to back up the conclusions,
This was not a listening evaluation.
But to date, we know what the DBT results have been. Rather dissapointing.
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Quote:
Originally Posted by mtrycraft
Are you speculating again something about me? Please don't.
Pardon my erroneous assumption. I didn't realize you were a test tone enthusiast. For other folks who enjoy listening to test tones instead of music, please disregard my comments.
Quote:
Originally Posted by mtrycraft
But you must have evidence to support your contensions.
Easy. You guys never talk about any tests that involve music. All of those tests involving complex and dynamic waveforms have seemed to slip my mind. Please enlighten me.
Quote:
Originally Posted by mtrycraft
How so. Be very specific.
Here again, I reserve my comments to only those who listen to music. The test tone enthusiasts can ignore my comments. Where do I start? Well the obvious cases are the virtually worthless value of THD, lack of jitter control in digital DACs, and the measured explanation why many early SS designs sounded like fingernails on chaulkboard - TIM. As for documentation, Mati Otata's paper goes back twenty years. Fortunately, engineers now understand that global feedback is something to apply in moderation.
Quote:
Originally Posted by mtrycraft
Actually, TIM is unimportant, really.
To the test tone enthusiasts, yes.
Quote:
Originally Posted by mtrycraft
Please, you have no idea of digital audio history in the real world.
You are mistaken. Do you like classical music? Probably not. Anyway, I participated in one of the earliest Telarc digital recordings of Stravinsky's Firebird at the ASO back in 1978. It was there I met Dr. Thomas Stockham who was one of the early digital recording pioneers with his Soundstream unit. Although Woods and Fenner handled most aspects of the recording, Stockham personally controlled the recorder. (sidenote: we are all saddened by his recent death)
http://www.legacy.com/SaltLakeTribun...rsonId=1772606
His 16 bit system sounded very good indeed during replays of the recording. The earliest CD players, however, sounded nothing like his tape machine. Many a wrong assumption was made with those units. I'll gladly sentence you to listening to my 1988 Magnavox if you think differently.
rw
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Easy. You guys never talk about any tests that involve music. All of those tests involving complex and dynamic waveforms have seemed to slip my mind. Please enlighten me.
All the DBT are with music. Threshold detect is by the most sensitive signals. That excludes music by default. But I thought you knew all this.
Where do I start? Well the obvious cases are the virtually worthless value of THD, lack of jitter control in digital DACs, and the measured explanation why many early SS designs sounded like fingernails on chaulkboard - TIM. As for documentation, Mati Otata's paper goes back twenty years. Fortunately, engineers now understand that global feedback is something to apply in moderation.
Yes, I know about Mati and the sound of caps too. Please cite his paper you are referring to.
In the meantime, please check this out:
http://www.dself.dsl.pipex.com/ampins/dipa/dipa.htm
Oh, he is a credible source to be contended with. This is not 20 years old wishfull thinking.
[b]You are mistaken.
That is always a possibility. It appears you are never.
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Quote:
Originally Posted by mtrycraft
All the DBT are with music. Threshold detect is by the most sensitive signals. That excludes music by default. But I thought you knew all this.
Really. The recent link to the Harman International labs used tones in their speaker DBTs. What I am really referring to in the context of cables is measurements based upon dynamic content.
Quote:
Originally Posted by mtrycraft
Yes, I know about Mati and the sound of caps too. Please cite his paper you are referring to.
Otala, M.: Transient distortion in transistorised audio power amplifiers. IEEE Trans. AU-18 no.3, 1970
Quote:
Originally Posted by mtrycraft
Oh, he is a credible source to be contended with. This is not 20 years old wishfull thinking.
Ok. Self likes class B amps. What is the significance of the link?
As to my having "no idea of digital audio history in the real world", what exactly was your point?
rw
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I mever nake mistakes.
:)
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Hi E-Stat,
Quote:
Originally Posted by E-Stat
All of those tests involving complex and dynamic waveforms have seemed to slip my mind. Please enlighten me.
I'm not sure if that is a serious question or if you're just picking at Mtrycraft, but it's a legitimate question, so I'll respond.
There is a long list of tests that use complex and dynamic waveforms. Commonly used waveforms include square waves, triangular waves, saw-tooth waves, white noise, pink noise, and all manner of MLS. MLS is cool because it is not only complex like real world signals, but also because it is deterministic. This lets us do all sorts of neat stuff, like plotting the real and complex transfer function of the device under test in both the time or frequency domain.
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Proponents of audiophile cables maintain that traditional tests cannot demonstrate the kinds of distortions that these cables reduce or eliminate but that they are audible. The do not produce DBTs to show that anyone can demonstrate that they are audible in any fair test. The least that they can do is invent an electrical test, any test to demonstrate that the waveforms delivered are more faithful. Square waves, Triangular waves and other periodic waveforms have not demonstrated this. So what will. If such tests have been performed, please specify where the reports of them can be found. I've never seen one.
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Quote:
Originally Posted by Chuck
There is a long list of tests that use complex and dynamic waveforms.
Perhaps I should have been more explicit. I have yet to see any discussion wherein those kinds of tests were applied to cables.
rw
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Quote:
Originally Posted by E-Stat
Perhaps I should have been more explicit. I have yet to see any discussion wherein those kinds of tests were applied to cables.
Oh, that's different. :) I get the impression that most of the people who post here have never done any kind of testing. Mostly I see people discussing tests run by others. In most cases the people discussing the test results probably don't have any idea what kind of tests were used to compile the data. MLS is almost a de facto standard in the audio industry, so you've probably seen many MLS measurements without realizing it. It has been used to measure cables quite often and the results are consistent with other test methods. If they weren't, MLS would be suspect.
When a cable or interconnect makes an audible difference it is always do to something that makes sense, never magic, and differences that can be heard can always be measured. The proof that we can measure far more than we can hear is found in the fact that we can measure so many things that we absolutely cannot hear under any circumstances.
This is not to say that every possibility has been examined, but just that the guys who will tell you that we don't test with complex waveforms or in the time (or frequency) domain are misinformed, or in those cases where they actually know better, they are lying. It's a lie that's been told so many times that lots of people now believe it. Perhaps all that misinformation was the real source of your question? If so I guess all I can say is that the information came from unreliable sources. There are plenty of them around. :)
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Quote:
Originally Posted by E-Stat
What is the significance of the link?rw
If that is over your head, then it is waste of time to explain it. But I wonder why TIM was not mentioned?
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Quote:
Originally Posted by mtrycraft
But I wonder why TIM was not mentioned?
Lack of intended scope for article, lack of space, lack of understanding, lack of interest, lack of desire to discuss that which he did not discover, etc.
You pick the answer. Where do you buy a Self class "B" amplifier?
rw
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