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Testing the waters: Skin effect Note:disclaimer at the end

24.186.183.161
Posted on November 10, 2002 at 17:55:17
John Escallier
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 So far, as a skeptical, open minded EE, I've seen a lot of interesting "factoids" presented on AA. So, Let's start the ball rolling in this new forum.

Skin effect and audibility:

The first site I looked at was very technically well written. But had an incorrect definition of litz wire. No testing was performed, generalities were stated. It appears no measurements were made. Looks like a standard E/M text.

The next very well written paper I read was Hawksford, 1995, which had a very serious measurement technique error (my contention, based on previous experience with the very same waveforms).

Skin effect is to be contented with at high frequencies, rf, microwave, terahertz, etc. And also at 60 cyle, where copper conductors over 4 inch diameter are hollowed out, as the inner meat of the copper is useless.

Given my "skeptical" nature, I would like to see some concrete evidence it affects audio in the ways that have been presented on AA. Phase smearing across the audio band, strange things that are "audible" but "unable to be measured using current measuring tools."

Links to web sites heavy on allegations, "new physics", anecdotal evidence....Might be interesting reading, but does not qualify as "testable, repeatable, concrete" evidence.

The first paper I reviewed which proved evidence by testing appears to be suffering from a testing error. Why was it not repeated, verified, shot down, etc....It was testable, even back in 1995. Is there any followup on that. No followup is not an option.

My statement that it is an error WAS ALSO NOT QUESTIONED. That too is not an option.

My statement that the litz wire description is inaccurate needs questioning also.

Here's the disclaimer:

I, and others who post here have strengths, and weaknesses. We all should be heard, and most importantly QUESTIONED (not ridiculed, harassed, or criticised). We all put our pants on one leg at a time (firemen not included here).

I make no claims as to the accuracy of skin effects statements on audio. I would like to get to the bottom of the claimed aural differences.

TTFN, John

 

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Guess I must be deaf, but I have been, posted on November 10, 2002 at 20:14:19
rcrump
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 building speaker wire from 16 gauge solid silver rod now for about six years commerically and my skin is doing fine whereas anything larger than 22 gauge is supposed to demonstrate audible problems according to Dr. Hawksford......I hear more problems with speaker wire made up of several smaller gauge wires as the focus becomes diffuse......

 

Re: Guess I must be deaf, but I have been, posted on November 10, 2002 at 20:48:22
Monstrous Mike
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 ...as the focus becomes diffuse......

You have highlighted one of the reasons I am hoping this forum will become useful. As a technical person, I have no idea what you mean by this statement. Perhaps we can define our communication of subjective evaluations.

 

Is this what we're going to discuss?, posted on November 10, 2002 at 22:00:09
Mwalsdor@cscc.edu
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 Hi Mike, I'm not here to debate Bob's point on any level, as he's capable of addressing that himself. What I'm questioning is your question. "I have no idea what you mean" - "... as the focus becomes diffuse...". This seems fairly simplistic. And your question argumentitive.

MikE

 

Want an answer ? Read: The Pooge Chronicles, posted on November 10, 2002 at 23:08:13
Sean
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 In a series of articles about modifying audio gear, Walt Jung and Richard Marsh took the time to educate "tweakers" about many different subjects. Skin effect was one of the subjects that they spent a quite a bit of time on. They cover all of the math and formulas as to how to work all of this stuff out and how they arrived at the findings that they did. It can be found on pages 16, 17 and 18 in "The Pooge Chronicles" as available from Audio Amateur / Audio Xpress. There are too many formula's and related discussion involved in trying to post it here, so i encourage you to read the articles for yourself and see what you think about what they had to say. Obviously, Jung and Marsh are NOT "knuckleheads" as they have been responsible for a great deal of "break-through" technology as far as audio electronics can be considered.

According to what they have to say, solid core 18 gauge shows reasonable linearity up to appr 20 KHz. In order to maintain bandwidth out to 100 KHz, one must stick with 26 gauge wire or smaller. In order to leave themselves some margin for error, many manufacturers have adopted 19 to 20 gauge as the dividing line rather than teetering on the fence at 18 gauge. One can somewhat get around the situation while using a heavier gauge IF the wire is "all skin" i.e. similar to Goertz "flat" conductors. Sean
>

 

In plain English...., posted on November 10, 2002 at 23:25:20
Sean
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 I think that Bob is trying to say that imaging is blurred and the soundstage becomes less solid as the strand count is increased.

If this is what he is talking about, i agree to a certain extent. Part of this may be due to the effects of having multiple paths for the signal to take. If all paths are not of equal length, it would be logical to deduct that the signal would run into staggered arrival times at the load. This would result in time smear due to the small phase shifts that would be taking place. Bare in mind that these shifts may be microscopic in nature in terms of percentiles and measurements, but i do believe them to be audible. Sean
>

 

Re: Is this what we're going to discuss?, posted on November 11, 2002 at 00:13:51
Duster
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 Although it would appear argumentitive, I think he is perhaps being honest and constructive at this point, with hope. The subjective realm of experience seems to have passed this fellow by over the years It is crucial for one to understand the lexicon of a particular field of interest and audio is a very complicated one, indeed, with much jargon. Not everyone can describe the various levels of fidelity and performance criteria that a fine design or device can emit but, that doesn't mean they can't appreciate it. I just wouldn't want him to design any cables... 4 sure.

 

Re: Guess I must be deaf, but I have been, posted on November 11, 2002 at 05:30:50
Phil Tower
 Bob:

I understand what you mean by the focus becoming more "diffuse", as I have heard the same effect from certain cables. The problem though that is immediately encountered in a forum such as this is that some, me included, are bound to argue that unless you have been able to demonstrate that you could detect these differences under blind conditions, and therefore eliminated all possible causes of your perceptions other than actual sonic differences, your statement of differences would not be acceptable, for example, in a scientific journal.

I hope we don't waste a lot of time here arguing as to whether sighted tests are reliable, because from a scientific viewpoint they simply are not. Of course, there is much to be said about the lack of reliability of DBTs that that have been reported to date, and, in my opinion, even much that can be said and debated over whether DBTs even conducted under the best of protocols will ever be able to reliabily test what may actually being heard by those of us who claim to hear differences during our at-home, long-term, sighted auditions.

 

See if this helps...., posted on November 11, 2002 at 05:34:24
rcrump
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 The topic is skin effect and audibility (I think) and I found 16ga solid core wire has less audible effects than running several 22ga wires to make up the same gauge........Hawksford, in his article, goes on about 22ga as the largest wire that should be used.....Regarding "diffuse" think of a pinpoint between your speakers where the soloist is located....The 16ga wire will achieve this whereas the 16ga made of several wires will make the soloist appear much larger or diffuse as respects image density....Duster, in 2003 I will have been building wires commerically for twenty years and can say for certain that all wire is crap, but some are less crappy that others....The only way to learn is to try these things and listen to them and formulate what works, what doesn't and try to discover the whys....My point is that skin effects are not as nasty as the articles make them out to be and I sure would like to know why as I have done the work in this area.......

 

Funny you should say this now ..., posted on November 11, 2002 at 05:41:35
BobM
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Posts: 1400
Location: Long Island, NY
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 I made a single run of CAT5 cables over the weekend (6 cables in a braid, running about 24 feet). They're breaking in on the left speaker. On the right I have a well broken in Jon Risch cross connect (also 24 feet) that I'm comparing against.

Now I only have about 12 hours on the CAT5, so take this with a big grain. The top end is still dull and the bottom hasn't filled out yet. But most obviously I hear that time smear. It's just not as sharp and distinct on the leading edges. I've got to give these a week or so more time before I'm really willing to say what they're capable of. I hope it improves. I'll probably shorten these and use them for the home theatre setup that I'm planning to buy myself for Christmas (wives never understand thee things, do they?).

Enjoy,
Bob

 

Well I guess i'll just go back and continue to, posted on November 11, 2002 at 05:54:03
rcrump
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 answer questions about which RCAs to use :-) Phil, I have training in scientific method and have some of my PhD work completed, but just don't see that this forum will go anywhere if it is necessary to prove the obvious....Differences in the sound of wires is a fact that needs to be dealt with. Some have tried and found the differences growing out of the grass at the bottom of a screen at 120dB down and that was for a Radio Shack wire whereas better quality wire was at 140dB down.....This makes little sense that something this far down is audible so I figure that the problem is FM as opposed to AM in nature and there are no standardized tests for this.....

 

Re: Is this what we're going to discuss?, posted on November 11, 2002 at 07:47:10
Monstrous Mike
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Posts: 571
Location: Ottawa
Joined: November 10, 2002
 I find many of the terms used to describe how particular cables or audio components sound to be ambiguous. I have some experience in another area of subjective evaluation, and that is wine tasting. There is a similar application of subjective terms to describe various wine tastes. But the terms in wine-tasting are something I can relate to as they are fairly clear to me.

In the descriptions of audio sound, there are many terms that I cannot actually assign to a particular sound. There are some that are straightforward like warm or harsh, but many seem to come out of thin air. Perhaps a more detailed look at what a term means to someone and the relating sound would help not only me but many others is our communication of how something sounds.

I know what diffuse and focus mean as singular terms but I cannot relate the term "the focus becomes diffuse" to a particular "sound".

I'm not sure why you find my inquiry "arguementative".

 

Re: Well I guess i'll just go back and continue to, posted on November 11, 2002 at 08:30:30
Phil Tower
 Bob:

I'm not suggesting that there is no place on this forum for subjective obsrvations and discussions as to what may be responsible for those observations. This is a hobby forum, not a university. But, I also think it is appropriate on this forum to discuss the limitations of subjective observations. I, personally, even though I have been beset with my own personal observations regarding differences in audio for over 30 years, will not attempt to impose those observations on others as proven fact, nor will I put much value in claims by others that perceptions resulting from sighted auditions must be accepted as fact.

I don't understand why all of this has to be so confrontational. Everyone brings a different view point to the subjects discussed at AA. I'm hoping that this forum will be one where we can debate fairly, but not feel that we simply have to out-shout one another or call each other idiots. I very much respect your observations, and I've put my money where my mouth is by buying your products. But that doesn't mean that I have to accept those observations as fact for purposes of this forum, unless those observations have been verified in accordance with commonly accepted protocols applicable to all scientific discussions.

 

What Limitations? (nt), posted on November 11, 2002 at 08:48:49
rcrump
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 :;;;

 

Re: Is this what we're going to discuss?, posted on November 11, 2002 at 09:05:31
Mwalsdor@cscc.edu
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 I thought I was giving you the benefit of the doubt (in one respect) - I apologize for the mischaractherization. I think you're looking into this more deeply than need be. I realize some descriptors boarder on the mystic but not in this case. The definiations your familiar are applicable for the intended use we're discussing. Realizing that certain terms can be vague and definitions are critical for understanding, I guess I (still) have difficulty following your query of the phraze. For me it raises questions beyond the meer definition you require.

MikE

 

Re: What Limitations? (nt), posted on November 11, 2002 at 09:06:17
Phil Tower
 Bob:

That subject has been discussed here at AA at length. I'm sure you have seen those discussions. If you don't agree with the benefit of removing bias by the use of control testing, then nothing I'm going to say will change your mind.

 

Re: What Limitations? (nt), posted on November 11, 2002 at 09:24:57
Rod M
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 You miss the point Phil. By definition, the scientific method does rely on subjective listening even in controlled testing.

 

That is, posted on November 11, 2002 at 09:54:20
rcrump
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 the way I feel about it as well......I trust my senses and they have gotten me through almost 55 years pretty well....When someone comes up with an extension of my senses that will tell me which way to twist a wire then I'll use it as a guide.....

 

To Rod and Bob:, posted on November 11, 2002 at 10:57:29
Phil Tower
 The ultimate test of the superiority of any cable or component must involve humans listening and making comparisons. But the question remains of whether sighted listening, with the accompanying potential of bias issues, is adequate.

If I possessed the talents to be a designer, I would have to make a personal decision as to whether to rely upon my own sighted evaluations or insist on blind testing. If I were confident enough in my own sighted auditions and believed that my customers would hear the same advantages I thought I was hearing, I might well choose to rely upon my own sighted auditions. That decision is simply one of many that each designer must make. In the end, his commercial success will depend on how well he makes all of those decisions.

If I were a scientist being paid to determine, to a reasonable scientific certainty, whether one cable actually sounded different than another, and if so, which one was better, I would insist on double blind testing.

As a consumer, I personally rely upon my own sighted auditions because what I am attempting to measure is whether replacing one cable with another results in a perceived increase in my enjoyment of my system, and if it does, whether the degree of perceived improvement is worth the cost I will incur in buying the new cable. I took two years, and listened, under sighted conditions, to literally dozens of different cables, from a variety of companies and representing a broad price range, before I settled on the ones I now use (which for what it’s worth, were probably about mid-way in the price range I was considering). Was there some complex placebo effect at work that caused me to reject all the cables I rejected, and buy the ones I finally settled on? I don’t know, and for purposes of my own personal enjoyment, I don’t care.

 

Phil, you missed the point altogether....I would, posted on November 11, 2002 at 12:46:17
rcrump
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 like a sensitive machine, an extension of my senses, to back up what I hear and allow me to make better cables.....DBT just does not do that as it relys on lots of very subjective ears for reliability.....If you are lucky you might find differences in cables using DBT, but you would only know that one cable was less crappy than the other and never be able to hone in on a definitive design for audio frequency wires.....I want to be able to run a reliable and valid test on the spectral analysis of wires so I can say, "Oh look at that seventh harmonic 120dB down! "So that is the problem and where that brightness is coming from" and go back to work to take out the kink.......Until that machine is an affordable reality audio frequency cable design will remain a black art.....

 

Re: Phil, you missed the point altogether....I would, posted on November 11, 2002 at 14:23:36
Phil Tower
 Got it. I just hope that doesn't mean you won't be participating in this forum. As I see it, all view points are important here.

BTW, I agree with you that most cables are crappy. However, between you and Alan, I've been able to equip my system with cables that in my own, unscientific, unreliable, subjective experience, have greatly increased my enjoyment of my own system.


 

Phil, I'm trying to spur someone with the best test, posted on November 11, 2002 at 15:38:21
rcrump
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 gear available to them to run some tests and get to the bottom of this.....Curl has a great test bench for testing amplifiers, parts and such, but is at the limit of his gear when it comes to running spectral analysis of wires.....We subjectively can hear a wire is bright in the upper mids compared to another, but they all measure pretty much the same on test gear available to high end audio engineers.....Point is let's get some valid and reliable measurements where we are not at the limit of the gear normal to audio engineering.....Anyone have some lab gear lying around? I have been criticized for calling audio frequency wire design an art form, but that is all it is until valid and reliable measurements are made.....It is sort of like trying to build a power amplifier without test gear.....Oh, how do you build an audio oscillator? You try to build a solid state amp without test gear :-)

 

Path length delays, posted on November 11, 2002 at 15:56:06
John Escallier
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 ##If all paths are not of equal length##


If you are takling inches, then you are not talking audio.. at 10% of light speed, signal propagation in a wire is not going to see inches.

Talk high megahertz, gig, tera, yes time of flight is an issue.
Wavelengths of kilometers, not exactly.

If you want to talk smearing, give me a much better answer than path length. That doesn't cut it at the frequencies we talk about.

Talk about eddy currents, resistive losses across cable, those kind of things. Talk about amp load, amp reaction to the load, non linearities of the stranded or braided configuration, wire to wire reaction of di/dt.

Phase smearing will not be caused by "textbook skin effect"; at least nothing in the audio range. The skin effect causes picosecond pulses to travel on the surface of the wire; at about 10% of the speed of light. Skin effect happend within the wire in the femto to attosecond speed. Not audio rates.


When you talk about wire "distortion", do not use voltage signals. Use current. Amperes. You need to push hundreds of watts into load, and measure accurately. I do not see that capability to do that ACCURATELY out there.

Hawksford fell into that trap. Used nice currents, but didn't realize measurement was "inaccurate"

(Don't forget, that statement is uncorroborated, I'm waiting for feedback on that.)

My desire for involvement here is to develop the ability to correctly measure what we are looking for. I make the assumption (a good one) that the talent is out there. But, it is necessary to re-think what to look for.

##shifts may be microscopic in nature##

For what you are talking about, path length, the shifts are not audible, and are over 6 ORDERS of magnitude (one million) beyond human hearing capability, as well as that far beyond power electronics, and electromechanical drivers. Remember, path length causes 50 to 100 picosecond delays.

Cheers, John

 

John, i think we are not nailing down enough variables., posted on November 11, 2002 at 17:12:16
Penguin
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Posts: 7116
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 Are we absolutely certain that the path delays are not audible? From a conventional thinking POW I agree, but I think one should perform the experiment to prove what path length delays become audible. There maybe one way to prove it is to make a multi-path cable with exactly the same length wires. Say 4 wires each 1000+- .1mm long. (It is within the limits of measurements) then make one where the 4 wires are within +- 20mm of each other and listen to both. If you can hear the smearing on the dissimilar length cable than the only difference that can cause it is path length. One would need to build a number of examples and correlate the results. Also need to build a single path control. If the three types all sound the same than the multi-path smear is a myth, need to look somewhere else. If the multi-path ones both sound smeared then there is some head scratching to be done and to come up with some other theories.

I always end up regretting when I start looking for a problem and deny the possibility that something trivial may cause it :-)

dee
;-D

 

Re: Phil, you missed the point altogether....I would, posted on November 11, 2002 at 18:40:41
Jitter_by_Coffee
 ""Oh look at that seventh harmonic 120dB down! "So that is the problem and where that brightness is coming from" and go back to work to take out the kink.."

Although this is an example, do you really think you're going to hear something that is 0.0001% of the signal? Especially when your playback equipment is going to be at least two orders of magnitude higher(0.01%). This would put that "distortion" you measured 40dB below your playback equipment's capability and that doesn't include your speakers.

The fact is, at some level, you can measure a difference between all cables. Only a DBT will tell you if any of them make it to the level of audibility.

 

16 Ga Silver Speaker wires, posted on November 11, 2002 at 19:21:39
Paul in Sterling
Audiophile

Posts: 637
Location: Northern Virginia
Joined: June 22, 2000
 Hi Bob Crump(rcrump):

Could you tell your opinion on the length limit for 16 Ga. Silver wires? I was thinking that 16 Ga. Silver wires might make some excellent rear channel speaker wires as well, if they can be used at longer lengths. Perhaps I could bi-wire the rears, increasing the signal carrying capacity...

I would love to hear any recommendations for dielectrics or wire configuration for the 16 Ga. silver wires as well. I appreciate any pointers you might offer and don't require any proof beyond your kind answer.

Thanks...

... Paul

 

It is my listening hat that allows me to hear, posted on November 11, 2002 at 20:03:23
rcrump
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 thing others cannot......What you say makes little sense in light of what can be discerned......I would just as soon take everything but meters and graphs out of the design of wires as tired of fumbling around in the dark......You way would make it more subjective as all you would do is hopefully discern between one wire and another....It does not address the issue of wire design at all.....

 

Re: 16 Ga Silver Speaker wires, posted on November 11, 2002 at 20:30:55
rcrump
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 I had a customer who ordered a 20' set, changed things around and just needed an 8' set and could not tell any difference....I was surprised a bit by this, but that is what he heard....A commercial product has to hold up and the solid silver will break if kinked so the wire has teflon extruded over it and then has PVC laid down over the teflon so the dielectric is about .25" in diameter....Special double wall heatshrinks have to be used as well to keep the ends from breaking off....The wire is given a very gentle twist is all....There are lots of tricks to making this work and will say it took me six months to get it to where it is now. It is unchanged now for six years...It would just about scrape the paint off the walls here in the upper midrange for a long while and I thought I would have to sell it as clothes line.....I can't say much more, but solid core copper is a lot more forgiving.....

 

Thank you Sir., posted on November 11, 2002 at 20:44:27
Paul in Sterling
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Posts: 637
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 Perhaps I'll try a longer length (longer than 20') in the future. I will certainly post my experience if I do.
Thanks...

... Paul

 

Path delays, posted on November 11, 2002 at 20:56:53
John Escallier
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Posts: 4425
Location: Long Island
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 ##Are we absolutely certain that the path delays are not audible##

Yes, absolutely. And that's why I say it here with "certainty"...To be questioned!!!!!! I personally doubt they are audible if in the nanosecond range, but have no proof to support that doubt other than the standard stuff taught in school. No measurements.

I'll work up some numbers to see what we're talking about. Perhaps someone else already has the info: At say 20Khz, stereo image, left-right imaging of one inch, 10 feet from sources...what kind of time delay would cause a shift of image one inch L-R at 20khz?

Sounds like a good experiment. Problems I envision:
What is smearing? If you can identify it's exact nature, we should be able to devise a test that can measure it.


How to make different lengths without some other effect causing a difference..for example, if you make a conductor longer in a braid by looping it out of the braid, how do you know the loop area didn't cause the effect, by changing one of the inductive paths. If it's not a braid, but a twisted group, pulling one wire out to get the extra length will alter it's signal relationships to it's neighbors.

I also think path delays are independent of the "skin-phase smearing". Path could be braid effects.

Your right about the variables. But, we also have to be careful that we change only one at a time, and identify ones that confound the experiment.

Cheers, John


 

is that recomendation based on the '95 paper?, posted on November 11, 2002 at 21:03:01
John Escallier
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 Or has he published more since.

Cheers, John

 

Re: Phil, you missed the point altogether....I would, posted on November 11, 2002 at 21:17:28
john curl
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Posts: 4708
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 Actually, harmonic distortion gives low numbers compared to complex IM distortion measurements. However, harmonic distortion is relatively easy to measure with conventional test equipment, and we can measure down to very low levels once we noise average and remove the distortion from the source oscillator. If we could use three or more properly spaced tones, we would get a higher measured result. The main problem is the higher order 'kink' in the transfer function or level released energy bursts that measure as higher order harmonic distortion, because this is a problematic distortion that will effect the sound of any quality piece of equipment. This has been known for about 70 years at least, and is still true today.

 

Re: Path length delays, posted on November 11, 2002 at 21:18:06
Sean
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 Sorry, i can't help you. If i had the answers that you were looking for, i'd be publishing my own articles rather than quibbling on a public forum.

As to your comments about a few inches of cable length not making a difference until you get up into very high MHz or GHz range, i would beg to differ. Then again, that is a different subject altogether and we'll probably never see eye to eye on it anyhow.

I've argued with EE's via the internet about similar topics for many years. They could never understand why i had the thoughts that i did until they saw what i was talking about first-hand. Just as "seeing was believing" for them, i'll stick by "hearing is believing" when it comes to audio. Just because you or i can't explain something doesn't make it impossible. On the same hand, just because i might tend to want to believe something to be true, doesn't make it so. As such, i try to be open minded to any ideas / suggestions that one can throw my way.

It would appear that you have at least a part of you that is open to exploring the how's & why's since you've stated that you think that the expertise and equipment is out there to measure what we are talking about. However, the rest of your post comes across as "we know it all and there is nothing left to learn about the subject". Between the two different tones within this last post i.e. the fact that you repeated classic textbook rhetoric regarding cable lengths, time smear, skin effect, etc... while asking for help on how to confirm that this situation really does exist tells me that you are torn about what you believe.

While i used to be in that position, i've come to realize that it doesn't matter what i believe. The differences in cables are audible, even power cords. Now THAT should get the ball REALLY rolling... : ) Sean
>

 

Re: Path length delays, posted on November 11, 2002 at 21:34:04
John Escallier
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Posts: 4425
Location: Long Island
Joined: October 3, 2002
 My comment was based on strand length differences, and different arrival times for signal propagating down the line. It is easily demonstrated that the speed of those signals are a good fraction of the speed of light, making the delays far smaller than any audio equipment in the world, amps, speakers, can reproduce. Unless you have tweeters capable of tens of megahertz reproduction.

And I would hope that the people that don't see eye to eye with me post here. It'd be pretty boring otherwise.

TTFN, John

 

Re: is that recomendation based on the '95 paper?, posted on November 11, 2002 at 21:40:45
john curl
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 Why don't you check his website and find out for yourself? Have you contacted Dr. Hummel yet? Hawksford is just as easy to contact. In fact, I e-mailed him about you today. His website shows 11 solid pages of technical titles of articles that he has written over the years. The '95 article is only a summary for audiophiles.

 

Re: Path delays, posted on November 11, 2002 at 22:08:23
Penguin
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 ##What is smearing?

I do not know, but if it is the sonic characteristic that some people attribute to path delays than the cable with varying path lengths should exhibit more readily than the one with constant path lengths :-). If both exibit the same problem than it is not path delays, it is something else.

##How to make different lengths without some other effect causing a difference

Big problem... i agree.

##I also think path delays are independent of the "skin-phase smearing"

Yes. need to make an another experiment with say 20 AWG and 40AWG single path cables same listening experiment would apply. If no difference then there is no audible effects of skin effect. The cable construction difference caviat applies here too. I do not know how to overcome that.

Once the audible differences of carefully constructed cables are established then one can start thinking about what to measure.


I have questions: The skin dept is defined as the depth at which the amplitude is reduced by e to -1 and has a phase shift of 1 radian. That would mean that there is signal traveling in the wire with a wide spread of phase shift right? Even at lower frequencies there can be components present at fairly high amplitude at considerable shift. Is the phase shif linear as you trave toward the center of wire? Meaining if i go in 1/2 skin depth the shift is going to be 1/2 of a radian? Just wondering, I do not remember any more how to do this :-) You have the Maxwels at your fingertips.

dee
;-D

 

Your hat has a problem..., posted on November 11, 2002 at 22:24:43
Penguin
Audiophile

Posts: 7116
Location: Delaware
Joined: August 5, 2001
 the green yellow pink indicator leds on the vertical post of the cooling device are not arranged in the proper order, this could lead to some coding errors causing electron collisions, resulting of sever phase shift of the rotator on top of the cap, intruducing undesirable modulations to the audible field. Need to inforce the correct order (top to bottom -> pink yellow green) , rewire with small silver post. Your listening hat will open new dimensions for you once the proper tweak is applied. Also the painted bottle behind the cap must be replaced with one filled with fermented grape juice.

dee
;-D

 

So...R Crump is a fan of R. Crumb...., posted on November 12, 2002 at 01:02:59
john dem
Audiophile

Posts: 1831
Joined: February 23, 2001

 

Re: It is my listening hat that allows me to hear, posted on November 12, 2002 at 02:13:40
Phil Tower
 Seems to me you and Bruce are talking about two different issues. As I said in an earlier post, a designer certainly will decide whether he is willing to trust his own sighted listening or insist on blind listening tests. I believe, for example, that Don Hoglund recently mentioned that he does employ blind testing sometimes in his work. You, on the other hand, obviously don't. Both of you seem to me to be producing product that is well received in the market place.

But I don't think Bruce is trying to tell you how you should design or conduct your business. The question he is addressing is the question of scientific verification of actual sonic differences between cables. I hope that I'm not understanding you to mean that because you have no question that there are sonic differences, we should all just take your word for it, stop trying to find ways to better test the claims of those of use who report hearing differences in our sighted auditions, and put an end to discussions of blind testing.

I cannot imagine a single competent scientist arguing that sighted listening tests, from a scientific viewpoint, carry any scientific reliability. Again, let's go back to my earlier post. If the University of Texas gave you a $1 Million grant to study and report on the question of whether it is possible for two cables of similar gauge and length to produce audible sonic differences, would you simply choose several different cables, call in some buddies, switch them in and out of your system without any blind controls in place, and report back to the university that yes, sonic differences are possible, because you and your buddies hear these differences when you switched cables in and out of your system?

 

Bought those Blues trading cards from Ramblin' Jack Elliot when he, posted on November 12, 2002 at 02:16:45
rcrump
Manufacturer

Posts: 4716
Location: Texas
Joined: April 20, 2000
Contributor
  Since: August 29, 2000
 when he was in town a few years back....

 

I'm getting old and glad I did most of the work, posted on November 12, 2002 at 02:53:03
rcrump
Manufacturer

Posts: 4716
Location: Texas
Joined: April 20, 2000
Contributor
  Since: August 29, 2000
 on cables and parts whilst in my thirties and forties...I still trust my ears and my ears only when it comes to voicing any product as I am my harshest critic and build the gear or wires to suit my tastes. If the product is commerical then that is nice, but I could care less as long as I was happy with the amp, DAC or wire....

All the scientific verification via subjective DBT testing tells one nothing about the best cable design at all......This needs to be measured as an extension of our senses or we will fiddle fart around doing DBT and probably never discover anything definitive.....Our ears are sensitive, but give me a machine that costs under $500,000 that I can plug in a wire and see what is going on on a screen and we'll start making giant strides and I won't call all wire crap any longer.......I would like to advance audio and not find the cream of the crap is my point in posting over here......

Paul in Sterling asked me how I got the TG HSR speaker wire to work and it involved six months of intensive work.....Percy sells a similar bulk wire and, unless Paul is very very lucky it will take him that long to figure out the formula and lets hope he doesn't burn out too many tweeters in the meantime....Building anything that just kicks ass is not easy at all and requires measurement as well as listening as the the strangest things can make large perceived differences....I would prefer to measure getting things as ideal as possible and then fiddle with the product to voice it to my taste....

I guess I'll go back over to Cables and keep recommending the proper RCAs as DBT will not yield anything definitive as respects design for audio frequency wires and essentially keeps us in the dark ages rather than advances our knowledge...

 

The hat has been cryoed and, posted on November 12, 2002 at 03:49:41
rcrump
Manufacturer

Posts: 4716
Location: Texas
Joined: April 20, 2000
Contributor
  Since: August 29, 2000
 most all the problems you mentioned have been addressed by this as well as proper break-in....I received the hat as a birthday gift years ago and guess I had best take it to the CES....It makes as much sense as the Bowler I wore last year....

 

Re: is that recomendation based on the '95 paper?, posted on November 12, 2002 at 05:02:58
BTW
Audiophile

Posts: 512
Joined: August 20, 2000
 Hi John,

What is Dr Hawksford's website ? I would like to read more of his articles. Thanks in advance.

Best Regards,

Bill

 

A less hurried response., posted on November 12, 2002 at 06:14:28
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 ##Then again, that is a different subject altogether and we'll probably never see eye to eye on it anyhow..... Just because you or i can't explain something doesn't make it impossible. On the same hand, just because i might tend to want to believe something to be true, doesn't make it so. As such, i try to be open minded to any ideas / suggestions that one can throw my way.##

It would appear that you and I do see eye to eye.

Oh, by the way, I had a power cord give me grief. At high levels, 1200w, a sub amp power cord gave my system audible distortion. Replaced it, stuff went away. I assumed it was simply contact resistance (worn out), and tossed it. That was high levels, huge distortion, in a system not designed for critical listening. I would have to assume a lesser cord issue can be evident in a good system.

Cheers, John


 

Excellllllente :-) (nt)., posted on November 12, 2002 at 06:46:06
Penguin
Audiophile

Posts: 7116
Location: Delaware
Joined: August 5, 2001
 ;-D

 

Re: It is my listening hat that allows me to hear, posted on November 12, 2002 at 07:31:02
Jitter_by_Coffee
 "thing others cannot......"

How's that?

"What you say makes little sense in light of what can be discerned"

In what way?

"You way would make it more subjective as all you would do is hopefully discern between one wire and another...."

Yes. Or one wire compared to many.


"It does not address the issue of wire design at all..... "

Didn't know that's what this discussion was about. But no, it doesn't. If one wire/cable distinguished itself from several, it will be no problem to measure why. Then you can finally get down to correllating what we hear to what we measure.

 

Re: Path delays, posted on November 12, 2002 at 08:32:22
Jitter_by_Coffee
 "I have questions: The skin dept is defined as the depth at which the amplitude is reduced by e to -1 and has a phase shift of 1 radian. That would mean that there is signal traveling in the wire with a wide spread of phase shift right?"

No. The one radian phase shift appears as a circulating current - an eddy current.

 

Re: is that recomendation based on the '95 paper?, posted on November 12, 2002 at 08:53:21
john curl
Manufacturer

Posts: 4708
Joined: May 16, 2000
 Just go to google.com and type in Malcolm Hawksford. That should get you there. That's all that I did, yesterday. There is a complete list of every one of his written contributions, his e-mail address, etc. He is at the University of Essex.

 

Re: Want an answer ? Read: The Pooge Chronicles, posted on November 12, 2002 at 10:13:18
john curl
Manufacturer

Posts: 4708
Joined: May 16, 2000
 Good input. I didn't know that they published the 'POOGE' Chronicles' but I would hope that some on this website would read them. By the way, last week I congratulated Walt Jung for winning an award in 'Electronics Design' for his contributions. He was listed among others, such as Edwin Armstrong and my old professor at UCB Dr. Pederson, who opened my up to a whole new world of electronic design. This is quite a tribute!

 

Re: Want an answer ? Read: The Pooge Chronicles, posted on November 12, 2002 at 10:15:05
john curl
Manufacturer

Posts: 4708
Joined: May 16, 2000
 me not my. Sorry, should have checked my spelling. ;-)

 

Skin, posted on November 12, 2002 at 10:49:52
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 ##Why don't you check his website and find out for yourself?##

Did. E-mailed, awaiting reply. One wonders what you said in you e-mail. :)

##Have you contacted Dr. Hummel yet?##

He's on the list of things to do. Not very high on it, but on it.

##His website shows 11 solid pages of technical titles of articles that he has written over the years.##

Yes, he is quite prolific. But I didn't see a followup on skin.

##The '95 article is only a summary for audiophiles.##

That's one SOB "summary", not too many people are able to follow it easily. Lots of E/M theory in it. But he's definitely up there.

In my initial post here, I was hoping for technical responses, not referrels to other's websites or postings.

TTFN, John

 

My partner is a bookworm and, posted on November 12, 2002 at 11:21:44
rcrump
Manufacturer

Posts: 4716
Location: Texas
Joined: April 20, 2000
Contributor
  Since: August 29, 2000
 he is trying to corrupt you like he is corrupting me - Beware!

 

It still produces EM fileds :-)., posted on November 12, 2002 at 12:16:42
Penguin
Audiophile

Posts: 7116
Location: Delaware
Joined: August 5, 2001
 cannot just discard it without analysis.

dee
;-D

 

Re: Path delays, posted on November 12, 2002 at 12:29:42
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 Yes, internally. but, the ends of the wire, in a two terminal model, do not show those out of phase currents. They tend to "counter" the bulk wire current in a way that starts from the inside out.

Hawksford contends that these out of phase currents have been measured at the end of the wires, as they are supposed to be storing lots of energy.
I'm not convinced by his article. I await e-mail from him.

As for path length. DUH!!!(mea culpa) I just remembered, stranded wire is comprised of a whole lot of different length wires. Unfortunately, interstrand resistance, and twist pitch modulated inductive coupling play havoc on the variables. It's not just a simple case of changing pitch and evaluating.

Cheers, John

 

I think part of the problem is that people assume…, posted on November 12, 2002 at 14:22:35
David Aiken
Audiophile

Posts: 5858
Location: Brisbane
Joined: September 25, 1999
 that because there are a number of tests that can be run and specifications that can be given, that we have all the tests and specifications we need.

Go back 50 years when there was THD but IM distortion wasn't known. People could hear it but it couldn't be explained and no doubt there were people who said if you couldn't measure it, it didn't exist. Why should we assume that we've got it all pinned down now?

Why shouldn't stuff that shows in the noise floor120 dB down on some existing tests be capable, in principle, of yielding an artifact up in the audible range on another test yet to be developed as Bb suggests? After all, If you play around with 2 frequencies above 20 kHz that can't be heard, you can produce a tone below 20 kHz which can be heard and we know how to do so quite reliably..

Once you know what's going on and how to test for something, you can really start to manipulate it scientifically as Bob says, rather than artistically by listening for the audible effects and operating on some personal rule of thumb or even intuition.

By the way, the point concerning our test batteries not being complete applies to DBT and other listening methodologies as well. They're not the last word because research and progress is always, if sometimes slowly, rewriting the last word. Even though they may be one of the best approaches we have at present, they aren't an appropriate way to test everything and they may prove not to be the most appropriate way, or even an appropriate way, to test for whether or not people can hear differences in cables.

Further, once you pin down what's going on, and understand it to the point where you can not only describe the audbile effects properly but have a test where the panel results reliable correlate with what people claim to hear, then the problem with the reliability of single listener sighted tests may well disappear. We know, for example, what THD sounds like and we have no problem accepting that people can hear differences in THD performance of 2 amps provided the differences are of a sufficient magnitude, even if they make that claim as the result of a sighted test. If you can identify a mechanism that causes differences in cables and it is known that differences of a certain magnitude in that parameter are audible, the reason to doubt someone claiming to hear that sort of difference in a sighted test totally disappear.

Sighted tests are only a problem when we're ignorant of what is going on. We have no problem with people making all sorts of claims about perceivable differences in things associated with their normal activities on the basis of what amounts to sighted tests, claims of the order of "this pencil is red and that one is black" or even, and much more problematically, "you're playing that music much louder today than you were yesterday". Sighted tests are all that is needed for much of what we need to distinguish and we'd never get through the range of activities we do each day if we couldn't rely on our normal use of our senses which basically amounts to "sighted tests".

David Aiken

 

lets see. if you are corrupted...., posted on November 12, 2002 at 14:42:07
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 How do I know you are telling the truth? If you're a liar, and you say your a liar.......Hmmm

I've already embraced the dark side of the force, your partner will find he is unable to corrupt me... Further.

 

I would..., posted on November 12, 2002 at 15:06:08
Penguin
Audiophile

Posts: 7116
Location: Delaware
Joined: August 5, 2001
 construct the multi path wires with minimal coupling between strands, say a quad helix with a 1" thread height and the strands 1/4" apart all wrapped on a 1/4" teflon tube, or foamed teflon. That way you would deal mostly with the path differences. But i still agree that creating functionally equivalent cables with only one variable changing is a very difficult task.

dee
;-D

 

There is something wrong here.., posted on November 12, 2002 at 15:21:20
Penguin
Audiophile

Posts: 7116
Location: Delaware
Joined: August 5, 2001
 ###If one wire/cable distinguished itself from several, it will be no problem to measure why.

You assume that what you hear, will somehow fall into one of the convenient categories of established measurment practices. (Remember it took years to come up with the IM distortion measurements to characterize the typically bad sound of early SS amps.) Cables may have a totally different phenomenom that is equally puzzling. You guys want to attach labels like it sounds distorted-> Ok lets measure distortion, rolled off -> measure freq response, but how do you measure the "it presents a much larger soundstage" differnce? You can hear it, but what is it?

You all also insist on that if it is different then everybody must be able to hear it. Well some people are color blind, but you would not insitute painting practices for all artist to only use colors that are easily distinguished by the majority of the viewers.

dee
;-D

 

Re: I would..., posted on November 12, 2002 at 16:01:01
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 ##construct the multi path wires with minimal coupling between strands, say a quad helix with a 1" thread height and the strands 1/4" apart all wrapped on a 1/4" teflon tube, or foamed teflon.##

How does that give different path lengths?

John

 

Topic...Definitely on., posted on November 12, 2002 at 16:47:00
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 ##The topic is skin effect and audibility (I think)##

I don't think....I know....At least that was my intent.

##and I found 16ga solid core wire has less audible effects than running several 22ga wires to make up the same gauge##

Standard E/M theory is that weird losses don't expose themselves when skin depth changes...Only that effective resistance goes up. That is at least what has been seen, tested, repeated throughout the world for the last 50 years. The fact that the skin of the conductor is where the current goes is not the problem, but that the effective resistance created may be a loss issue. That certainly jives with your experience.

##Hawksford, in his article, goes on about 22ga as the largest wire that should be used##

Is that based on skin depth solely, or on his measurement? The one I'm questioning. All the power guys out there worry about skin depth for dissipation reasons only. There is no consideration for "storage of energy" within the cables at the level he would suggest. Measurement of current within a conductor at high currents using a DCCT (a very interesting, very accurate way of measuring current) do not produce the waveforms he "may have based his recommendations on". (Again, I have to point out that my statements are neither proved or disproved.)

##Regarding "diffuse" think of a pinpoint between your speakers where the soloist is located....The 16ga wire will achieve this whereas the 16ga made of several wires will make the soloist appear much larger or diffuse as respects image density##

Let me add to this statement......
Human hearing identifies a source location by two things...Phase (or time of flight to each ear), and amplitude. I'm working out the details for a typical audio room scenario, but the initial delta time numbers are interestingly low. I'll post in a day or two. But suffice it to say, for an inch or two variation in perceived vocal location, delta T's are in the tens of microseconds. It may not be that we hear 100Khz signals, but may perceive directionality at vocal frequencies from time cues of that speed. More on that in another post.

##Duster, in 2003 I will have been building wires commerically for twenty years and can say for certain that all wire is crap, but some are less crappy that others##

Geeze, sounds like my girlfriend's lament about guys....Of course, she's not talking about me!!!!

##My point is that skin effects are not as nasty as the articles make them out to be and I sure would like to know why as I have done the work in this area##

You just summed up my whole reasoning for the posts.

TTFN, John

 

I would vary the four conductors in legth.., posted on November 12, 2002 at 17:56:52
Penguin
Audiophile

Posts: 7116
Location: Delaware
Joined: August 5, 2001
 and buid a control of even length. With this approach you could only hide small variations but is it not what we are trying to prove?


dee
;-D

 

Re: There is something wrong here.., posted on November 12, 2002 at 18:08:55
john curl
Manufacturer

Posts: 4708
Joined: May 16, 2000
 You are correct, Penguin. In the early days we had SMPTE style IM measurements down to .001% This was 30 years ago. We thought that this was better than THD, and easier to measure. It was quieter too, because the measurement bandwidth would only be 1kHz or so, rather than 80kHz, normal with THD measurements. We found, to our amazement, that the SMPTE IM did NOT see TIM or slew rate limiting at all! This got us to make new measurements or to revert to high frequency THD measurements to get a more accurate assessment of how an amplifier actually passes an audio signal.

 

Sorry, I wasn't very clear in my question., posted on November 12, 2002 at 18:36:21
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 How do you connect four different length wires together at each end without introducing loops, or separating them from the bundle.

Cheers, John

 

I was talking about rather small differences., posted on November 12, 2002 at 19:06:33
Penguin
Audiophile

Posts: 7116
Location: Delaware
Joined: August 5, 2001
 you can cheat 20 mm out of 1000mm slacking off one wire, and tightening another. I know it is a problem but i do believe it is doable since i have managed to get the ground and hot different lengths on one of my silver cables by about that much even though i thought i was winding them pretty evenly. As i said constructing cables that only change one variable at the time is going to be a b..ch :-). I am trying to come up with some practical approaches. Feel free to shoot holes into them they are put up for target practice , let's see if there is something that you can not turn into a sieve.

dee
;-D

 

Re: I think part of the problem is that people assume…, posted on November 12, 2002 at 19:21:27
Phil Tower
 By the way, the point concerning our test batteries not being complete applies to DBT and other listening methodologies as well. They're not the last word because research and progress is always, if sometimes slowly, rewriting the last word. Even though they may be one of the best approaches we have at present, they aren't an appropriate way to test everything and they may prove not to be the most appropriate way, or even an appropriate way, to test for whether or not people can hear differences in cables.

I very much concur. Hopefully, over time at this forum, we will be able to explore the current limitations posed by blind testing due to lack of agreement on how they can best be run to duplicate as closely as possible the conditions of extended, at-home auditions, while at the same time removing potential sources of bias. Perhaps people will even be able to come up with a protocol that most can agree upon.

Sighted tests are all that is needed for much of what we need to distinguish and we'd never get through the range of activities we do each day if we couldn't rely on our normal use of our senses which basically amounts to "sighted tests".

The differences I have perceived in cables and components over the years have seemed as real to me as most daily experiences. Yet, I have heard a number of anectdotal stories of people who were convinced that they could hear differences, but who were unable to do so under blind testing. I've never participated in a blind test myself, and I really couldn't say with a lot of confidence that I'm sure I could pass one.


 

Re: I think part of the problem is that people assume…, posted on November 12, 2002 at 19:21:56
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 ##that because there are a number of tests that can be run and specifications that can be given, that we have all the tests and specifications we need.##

Bingo

TTFN, John

 

Re: I was talking about rather small differences., posted on November 12, 2002 at 19:27:51
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 ##Feel free to shoot holes into them they are put up for target practice ##

Gee, I thought that was my line. But with theories.

Cheers, John

 

And Im trying to spur the people with the best "mind gear", posted on November 12, 2002 at 21:00:32
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 I'm not sure if it's the gear that's not up to par. I think it may be "us". What are we really looking for?

I'm tryin to spur that line.

TTFN, John

 

CAT 5 CABLE!!! Doesn't that have two different pitches????, posted on November 12, 2002 at 21:14:58
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 I don't remember all the details, but I just remembered the cat 5 cable had an interesting modified "X" wire spacer inside the bundle, holding the twisted pairs apart. I also recall something about the twist pitch of pairs being different to lower crosstalk. Of the four pairs, the opposing pair had the same pitch, while the pairs next had differing pitch.

Perhaps it was cat 5-E I'm thinking of. But if the pitch is different, I wonder....

Cheers, John

 

Re: And Im trying to spur the people with the best "mind gear", posted on November 13, 2002 at 07:34:40
Phil Tower
 Well, John, this seems to be the elephant many want to ignore. What the hell is it we are looking for and why? Bob seems convinced of the reliability of his own sighted hearing. My own sighted comparisons seem quite real to me too. But neither one of us can claim any scientific validity unless we have subjected ourselves to blind testing. I have not, and therefore make no claims about the validity of my perceptions, even though I have experienced them for decades and in fairly consistent patterns.

Bob seems to want to avoid all this, and apparently doesn't think much of those of us who find the question of trying to determine if these differences so many of us are fairly convinced are real, are in fact real, or simply the product of placebo. I'm quite comfortable with Bob's approach as it relates to design - I think I've proved that by buying a number of his cables. Apparently his perceptions and mine are fairly consistent. But when it comes to a dispasionate, scientific discussion of the subject, that seems to me to be an entirely different matter.

So, beyond that, and more germane to your question, I understand that science usually requires verification of a particular phenomenon before it spends a great deal of effort investigating its cause. If we can't verify scientifically that perceived differences are even real, aren't we putting the horse before the cart by running off to try and identify "causes"?

It seems to me that even if we have the most sophisticated test equipment at our disposal and are able to measure some thing or things that haven't previously been measured, the real question still remains as to whether such measurements have any relation to sonic effects that can actually be heard.

You have been criticized here because you supposedly don't have the "experience" many of us claim to have with high end gear. I have over 30 years of such "experience" but I have never demonstrated that the differences I perceive are due to actual sonic differences. To the best of my knowledge, there are no reported instances where anyone has demonstrated that the differences they claim to perceive between different cables or components are due to actual audible sonic differences, with the possible exception of speakers. So in my opinion all of us are pretty much on a par with one another with respect to the "experience" required for a scientific examination of audio cables.

 

Re: Want an answer ? Read: The Pooge Chronicles, posted on November 13, 2002 at 09:23:17
HiFi Guy
 That's why they make Litz wire. It contains a bunch of very small strands that are insulated from each other to obtain a larger guage wire. This gives the current at very high frequencies more surface area and lowers the resistance, since HF current tents to travel along the outer surface of a conducter
When I was in the Radar manufacturing business it was used extensively in high performance deflection yokes designed for military use. I was not aware that it was an issue in the audio range, as tests we did showed that the skin effect only srarted to make a difference in performance, at least in radar systems, at around 50 MHZ. But if some peaople think it sounds better, so be it. It certainly can't hurt to use it in speaker wire.

 

Re: Guess I must be deaf, but I have been, posted on November 13, 2002 at 09:30:14
HiFi Guy
 In the multistrand wire you tested, were the strands insulated from each other. Electically solid wire would seem to be a poor choice for audio speaker wire. I've never listened to it so can't comment on how it sounds. Regards HFG

 

Re: And Im trying to spur the people with the best "mind gear", posted on November 13, 2002 at 09:57:41
John Escallier
Audiophile

Posts: 4425
Location: Long Island
Joined: October 3, 2002
 ##You have been criticized here##

I have?
I recall some thinking I need "experience" in esotheric audio to know what I'm looking for. But I contend, as you have elucidated (cool word, I may have even used it correctly), that we need to figure out what it is we are looking for.

I just started a post at the top, talking about hearing perception concepts, starting with "time of flight". I'm working out the details of how to test one's perception as to sound direction vs delay, what kind of delays we're looking at. Some kind of wave file, I would think, using headphones, and determining the perceived direction of sound.

I'll be trying my home wave editing software tomorrow night, delaying a mono signal left to right, at whatever increments I can get.

Perhaps, someone out there has a better software package than I for this. I'll keep everybody posted.

TTFN, John

 

Re: There is something wrong here.., posted on November 13, 2002 at 21:23:20
Jitter_by_Coffee
 "You assume that what you hear, will somehow fall into one of the convenient categories of established measurment practices. "

Well, I would hope so! :~) But I guess that would be too easy then, huh.

"You all also insist on that if it is different then everybody must be able to hear it."

No. Otherwise we would only use a single testor in each test. No one does that. We use a minimum of 50 people for casual listening tests at work.

"You guys want to attach labels "

I don't understand who you're talking about here. Quite frankly, many of the things I've seen talked about on AA and other places, I cannot find a reliable definition or method of quanitization for anywhere.

 

Of course DBT's can't verify some of that!, posted on November 14, 2002 at 18:01:24
jj
 You say ** even much that can be said and debated over whether DBTs even conducted under the best of protocols will ever be able to reliabily test what may actually being heard by those of us who claim to hear differences during our at-home, long-term, sighted auditions.**

Since SOME of that sighted perception will be due to things other than acoustic stimulii, a DBT will never be able to reliably show the existance of that part, yes?

A note here, Phil, humans are wired to substantially overdetect events and differences in auditory stimulii. It comes about via several effects, but the long and short of it is that merely thinking something MIGHT be different is enough to cause people to redirect their attention. This means, because of the way auditory memory works, that they will, factually, RECALL DIFFERENT THINGS, even though the stimulii may be the same.

It's not a hallucination or anything like some of the illspeakers here seem to think, it's simply how people work. Not "some" people, either, as far as I can tell, "all people". It's part of the hardware.
JJ - Philalethist and Annoyer of Bullies

 

Re: Of course DBT's can't verify some of that!, posted on November 14, 2002 at 23:09:39
Phil Tower
 Since SOME of that sighted perception will be due to things other than acoustic stimulii, a DBT will never be able to reliably show the existance of that part, yes?

Yes. In fact, all of the sighted perception may be due to things other than acoustic stimuli and DBTs will never measure those things, but, as I understand their purpose, they are designed to tell us when our perceptions are due to things other than acoustic stimuli rather than actual acoustic stimuli.

Maybe I can illustrate what I was trying to say by an example. Assume I have two sets of interconnects at home, A and B. I switch them in and out of my system and listen to them, each time knowing which set I’m listening to. I determine that they sound noticeably different. You then come to my house and subject me to a DBT with these two sets of cables using the best testing protocol you know. We run 50 trials, and you analyze the results and determine to a 95% confidence level that I was unable to distinguish between the two sets of cables under test conditions.

My question then is, does that mean that we can conclude to a reasonable scientific certainty that my sighted differentiation between the two sets of cables was due entirely to expectations or placebo and not actual acoustic stimuli; or is it possible that there is some inherent flaw in the test itself that prevented me from differentiating between the two cables under test conditions, whereas under non-test, sighted conditions my differentiation between the two cables was actually based on acoustic stimuli. I assume from another of your recent posts that your conclusion would be that based on the test results, we could conclude to a reasonable scientific certainty that my sighted differentiation between the cables was not due to acoustic stimuli.


 

Hm., posted on November 15, 2002 at 18:17:56
jj
 Your hypothetical test, assuming that it was done well, shows only that THERE IS NO AUDIBLE DIFFERENCE IN THE TEST SETTING.

That's all. It does not necessarily relate to other test settings at all.
JJ - Philalethist and Annoyer of Bullies

 

Re: Hm., posted on November 16, 2002 at 07:09:10
Phil Tower
 Your hypothetical test, assuming that it was done well, shows only that THERE IS NO AUDIBLE DIFFERENCE IN THE TEST SETTING.

I fully understand that. I don't think anything in my post should be read to suggest otherwise. But elsewhere I have questioned whether results in a test setting can be extrpolated to apply to what actual sonic stimuli (to borrow your term, which I like) can be detected with regard to the same cables being tested in a more casual, long term, sighted, at home audition. I'm fully aware that the sighted audition may very well produce perceptions of differences that were not shown by the test. The real question is whether, as a result of null results of the test, can it be said that any perceived differences resulting under sighted conditions in a casual at-home environment, have to be due entirely to expectations, bias or placebo.

Seems to me that it is fairly important for lay people such as myself to get clarity on this, because as Rod has pointed out, so much of the arguments in this area seem to center on the broad question of the validity of DBTs in general, when in fact the focus should be on the reliability and significance of individual test results. All of this may be clear to you professionals, but I suspect many of us lay people are confused, and that confusion can lead to debates that get so intense that they can lead to extremely nasty and harmful personal accusations being hurled back and forth.
This thing gets so emotional and intense that within the first week of the creation of this forum, someone is already urging a boycott and calling those of us who participate "pitiful".

In addition, regarding the limitation of a particular test, elsewhere, I have argued that the burden of proof in one the side of the person who claims that cables of similar gauge and length can sound different, because in order to prove the falisity of that statement, one would theoretically have to test every combination of cables employed in every conceivable combination of components.

 

Well, any test needs to be reviewed., posted on November 16, 2002 at 13:40:17
jj
 And it's hard for a layperson to do that, unfortunately.

As to proving the negative, it does require enumeration. No test reads on anything beyond that test, at least without a great deal of investigation into the two situations being compared, and that is still difficult and risky in the general case.
JJ - Philalethist and Annoyer of Bullies

 

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