Cryo

Guest · Jul 1, 2003

""Besides, even if I could measure a difference, I could not prove that this is audible...  what's the use?? ""AE

Because if you can measure a difference, and it proves to be the aspect that makes it sound better, then an engineer can optimize that aspect..Thereby making better sounding product in a consistent manner.

When transistor die attach evolved, it was known that there was a difference between units, but you couldn't see any difference between them..When theory advanced enough that a measurement system could be developed where die attach could actually be measured electrically, bingo..100 % known good units...And, as an added bonus, 100 % process control feedback.

If a difference exists, it will eventually be found..That's the reason I hit the forums.
As for testing outlets..I'd concentrate on actual equipment pluggged into it, and try to find out how the outlet affects the equipment.

But I'm just real wary of the pseudo-science..Many times, belief in such sets the art back decades..

Cheers, John

gene · Jul 1, 2003

Something important to note:

Just because one believes they hear a difference doesn't necessarily mean there actually is a difference. Its all about perception. If one is conditioned to believe they will hear a difference prior to listening themselves, than they may certainly perceive that difference based on already instilled prejudices. What makes it even more challenging, is cable sonic differences are very minuet between well designed products. Taking an identical product and comparing sonics between a cryo vs uncryo treated version is even more minuet if at all audible, let alone measurable.

Never lose sight of the fact that there are many more important variables than cables in a high performance audio system that have significantly more impact than a cable change (IE. Room treatment, speaker placement, proper system calibration, etc). I have found that most people who enjoy endlessly debating cable sonics usually don't have these basic issues optimized in their own systems.

Guest · Jul 1, 2003

""Just because one believes they hear a difference doesn't necessarily mean there actually is a difference.""GDS

It's a two by two state diagram..

Hear a diff/  don't hear a diff..

Is a diff/    Is no diff..

DBT stats can be used to try to sort it out.

Your statement:

""What makes it even more challenging, is cable sonic differences are very minuet between well designed products.  Taking an identical product and comparing sonics between a cryo vs uncryo treated version is even more minuet if  at all audible, let alone measurable.""

is quite true.  Complicated by the question"what is it we look for electrically"?

Cheers, John

rode · Jul 1, 2003

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Quote </td></tr><tr><td id="QUOTE"> ... Complicated by the question"what is it we look for electrically"?</td></tr></table>

For any cable at audio frequencies, we all know what to look for. Resistance, Inductance and Capacitance. The frequency response and power loss is easily measured at any power level with a known amplifier, and that will take R and L into consideration, as well as skin effect (if you think it's relevant).

Very accurate comparisons can be made with a slightly modified version of a Wheatstone bridge. By this means, any variation or change can be readily identified by virtue of the loss of null (which is extraordinarily sensitive), although the reasons for the change may not be readily apparent without very sensitive measurement equipment.

The only other "change" might be in distortion levels, but I know of no (sane) research that has ever proven measurable distortion in a metallic conductor - perish the thought!  Even the distortion meter and generator would have to be wired with magic to eliminate the distortion in their internal wiring.

I think this discussion is pushing the boundaries of sanity. Differences are common, and are almost always a question of perception - a DBT will reveal that there is usually no discernable difference (with cables of equivalent RLC) and a relatively benign speaker load will allow most cables of almost any construction (that isn't just crazy) to sound indistinguishable in a DBT.

Haven't these topics been done to death already? They have been covered, re-covered, regurgitated and expounded ad nauseum.

Guest · Jul 1, 2003

I'd like to add something to the debate.  

I spend a considerable amount of time with Engineers at Lockheed Martin, Harris, Northrop Grumman and Raytheon.  These guys are working on cutting edge technology with combat vision systems, radar sensor, infrared systems and all sorts of complex electronics.  They deal with both audio and high frequencies on the order of over 1GHz; way above and beyond audio.  Furthermore, they contiunally try to improve performance and minimize loss in improve bandwidth in order to prevent video signal black out during combat.  Contrary to most people views, these companies are spending a great deal of time in R&D using cutting edge designs.

Why is it that none of the Engineers in the Aerospace industry, working on the latest technology with the most updated equipment available, ever cryo-freeze cables or concern themselves with strand jumping?

I've broached both these subjects with some of the high level RF-Engineers and systems designer during friendly discussions, and they litterally wet themselves when I tell them about what has become of the audio cable industry.  

Kid Charlemagne

gene · Jul 1, 2003

Kid;

The truth of the matter is exotic cable vendors sometimes have to stretch the truths and bend them towards their will to justify reasons that make their products "better" or different. After all, if cable vendors were to come out and say $1/ft 10-12AWG wire is all you need for audio applications, where would their profit margins go?

In addition, many audiophiles won't accept this, despite unequivocal evidence presented. Many simply feel if it is too cheap, it can't be good.

Am I being too cynical?

Guest · Jul 1, 2003

""For any cable at audio frequencies, we all know what to look for. Resistance, Inductance and Capacitance. The frequency response and power loss is easily measured at any power level with a known amplifier, and that will take R and L into consideration, as well as skin effect (if you think it's relevant).""RE

Hi Rod..been a while..

Can you show me how much temporal shift occurs when a slew rate changes, forcing the stored energy within the wire to go away?  Can you detail the difference between the energy storage of a #12 wire at 50 hz vs one at 10Khz, and what happens when the two are superimposed??  I really wish I could put pictures here..

I can't..  But, if the diff exceeds 20 usec, humans can hear it in spatial image location.. I don't know if that .03 microhenry difference makes a difference...

Skin effect is a frequency dependent effect, where the current profile changes, depending on the rate of change of the current(not frequency, as is normally considered.).  As such, one must consider the difference between the energy storage as a result of current density profile.  I'm afraid I have to draw something to really make myself clear...

""Why is it that none of the Engineers in the Aerospace industry, working on the latest technology with the most updated equipment available, ever cryo-freeze cables or concern themselves with strand jumping?""KC

I've no understanding of how cryo could do anything to affect copper...and I work with superconducting magnets, both liquid helium and liquid nitrogen..

But strand jumping.....If your engineering friends would like to understand that, send them to me, and I'll explain it to them..Trust me (actually, don't trust me, listen to your friends, after they talk to me..).  It exists..It has to..for skinning to occur.

BTW...to answer your question...because they don't have to.  It has no bearing on what they do.  They are concerned either with power transfer, at constant frequency, or hf stuff, where the full bandwidth of signal is skinning heavily.

Cheers, John

Guest · Jul 1, 2003

Boy, I really made that clear...

""Skin effect is a frequency dependent effect, where the current profile changes, depending on the rate of change of the current(not frequency, as is normally considered.). ""

Skin effect is always taught as a frequency dependent effect, with sine wave excitation used as the example....It is the conductor's reaction to a change in current (slew rate).

Sorry bout that..

Cheers, John

gene · Jul 1, 2003

Hi John;

Based on our work together, you should know that RLC cable metrics cause group delay changes in the 10-100's  nsec range, even with some of the worst measured cables.  This is on an order of 100-1000 time less than is perceivable by the human ear.

As for Skin Effect, I thought we beat that with a rubber hose.  I am going to be bold here.  

SKIN EFFECT HAS NO AUDIBLE RELEVANCE ON SPEAKER CABLES.

If there is a mechanism other than frequency dependence of RLC of a cable causing audible changes in cables, then one should find another reason since the classical and proven models of Skin Effect prove that it can't be the cause.

Look as all of my data.  If anythin skin effect helps the upper frequency extremes by reducing internal inductance.  The increase in AC resistance was far less than I calculated, probably since all of the cables I evaluated were stranded and my modeling was based on solid core.  

Strand jumping does happen, no argument there.  Does it lead to audible distortion?  Most likely not.  Has anyone accurately ever measured this distortion?  Not to my knowledge.  Is there any test equipment sensitive enough to measure it?  You got me.  However, I have used an Audio Precision One (>120dB resolution) and have seen no measurable distortion on a stranded wire.  No cable vendor ever furnished any credible evidence to support this issue.

Cables have become way too overhyped IMO.  As the president of an Audio website, it troubles me to see so much fruitless and un-quantifiable claims about trivial issues for the intended application.  Audiophiles sometimes lose sight that a majority of hardware vendors have problems designing flexible and usable preamp/processors, low noise amplifiers, accurate loudspeakers, buttressed with recording engineers spitting out distorted and overcompressed CD's, while most audiophiles don't even consider the importance of an acoustically well treated room.

Audioholics · Jul 1, 2003

John,

I know you enjoy the banter - but I think this exchange is... (I'll put it gently) semantic. You have presented some great input in the past that makes me think that you are just playing devil's advocate right now.

And we all know what eventually happens to the devil.

Guest · Jul 1, 2003

""that makes me think that you are just playing devil's advocate right now.""Hawk

You obviously don't know me..

""I am going to be bold here.  
SKIN EFFECT HAS NO AUDIBLE RELEVANCE ON SPEAKER CABLES""GDS

I am unable to prove you wrong...yet..perhaps never, but not for lack of trying..

None of the equipment you have ever used is capable of looking for that which I hypothesize..I have searched, to no avail.

I look for(actually, am designing) a piece of test equipment which is capable of watching the hf phase shift when a lf signal is introduced.  That is the ramification of skin effect..Not a simple change in current profile vs frequency, but the overall energy distribution as a result of slew rate changes..

""classical and proven models of Skin Effect prove that it can't be the cause""GDS

The classical form of the skin effect equations show that cross sectional resistance as a result of current density profile changes is not significant.

However, the profile of a hf signal, with the current tending towards the surface, has a different energy profile and storage.  Think about it...A current profile that is uniform across the conductor, vs a profile which tends towards the surface.  The shift between profiles requires energy..either a gain, or a loss..Because the current has to cross a magnetic field to do so..

As for KC's friends...you believe strand jumping occurs, they don't ...matter of understanding..They will, once they realise the issue..

For cryo, the origional topic...my contention is...I have nothing to support it technically..but I fear my technical knowledge is rather limited..so I cannot state an absolute..

Cheers, John

rode · Jul 2, 2003

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Quote </td></tr><tr><td id="QUOTE">I am unable to prove you wrong...yet..perhaps never, but not for lack of trying.. (JN)</td></tr></table>

In an earlier post, I suggested a Wheatstone bridge, which allows a complete null.  Now, once you can obtain a perfect null (maybe with a different method, such as phase compensated substraction), then you inject (and null out) a 400Hz tone for example. There is nothing there at all if the null is done well enough.

Then, do the same with a 20kHz tone (leaving the other nulling circuit in place). You will probably need to reiterate these static tests, since there will be some interaction between the nulling circuits.

Now, apply both tones at once.  Do you honestly expect to see additional "sideband" signals because of this?

If your skin effect theory is right, then it should be obvious - some of the 400Hz tone should re-appear because the null is no longer perfect - its amplitude must change according to your theory.  Likewise, the amplitude of the 20kHz tone should also be modulated.

This test would need to be run with extremely short wires and a 10m length to make sure that there are no anomolies caused by the test setup itself.

What percentage chance do you reckon on that you will see the effects that you claim will occur? (i.e. modulation, or possibly sideband generation).

My guess is 0%, and I'd be interested to hear yours.

For any of the above to reveal modulation, sidebands or any other similar phenomenon, the metallic conductors used must posess some degree of non-linearity (i.e. distortion).

Want to revise your guess?

Guest · Jul 2, 2003

""Want to revise your guess?"" RE

Nope..

""Now, apply both tones at once.  Do you honestly expect to see additional "sideband" signals because of this?""RE

Nope..

""If your skin effect theory is right, then it should be obvious - some of the 400Hz tone should re-appear because the null is no longer perfect - its amplitude must change according to your theory.  Likewise, the amplitude of the 20kHz tone should also be modulated.""RE

Nope..and Yep..

""For any of the above to reveal modulation, sidebands or any other similar phenomenon, the metallic conductors used must posess some degree of non-linearity (i.e. distortion).""

Hmmm...yep and nope..

Excellent thinking..I'm afraid I don't recall that post you mention.

What my hypothesis expects to see is phase shift of the hf signal, so your nulling method should show the hf signal when the lf signal is introduced.  But, off the cuff, I don't think there will be any new frequencies introduced, that would have been picked up by IM test hardware long ago.

The collapse of the internal inductance component of the wires (.03 uhenry per foot, pair, max) when slew rate suddenly rises requires a spacial re-alignment of the current within the conductor.  That requires energy.  I just don't know how that energy manifests during the re-distribution, either while going to the hf profile, or the lf profile..and I don't know if the energy required is significant enough to be measured..

Hey, I said it's a hypothesis..And I've predicted a testable effect..That's what we're supposed to be doing..It's pissin in the wind to predict an untestable one.

My slant on testing is to run a cable with a really good load, and use a very good IA pair, one at each end of the cable.  Connecting the IA to the cable means I have to worry about field intercept issues.  I've got the load covered, but still wrestle with the amp end pickup.  But the procedure requires the exact same two tone component sequence you mention.

""My guess is 0%, and I'd be interested to hear yours.""RE

Non zero..but possibly in the mud, way below what I can measure.  The best case would be getting a result that others can try to verify or refute, the worst case, is I set an upper bound on the effect, that being the resolution of my setup.

And don't forget, we're talking about human audibility of skin effect here.  So, to find temporal shifting below 5 to 10 microseconds would be an academic find, not really an audible one.

Cheers, John

Audioholics · Jul 2, 2003

Better run these tests in a vacuum as well... just to be safe.

Guest · Jul 2, 2003

The dielectric constant of a vacuum is of no concern here..nor the anbient temp, nor.........Oh....a joke!!!  Geeze, don't kidd like that...Hawksford may hear it..

The only vacuum around here is the one between my eyeglass holders, btw..

Cheers, John

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