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Author Topic: Microphone Cables - An Intelligent Discussion  (Read 62327 times)

Klaus Heyne

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Re: Microphone Cables - An Intelligent Discussion
« Reply #15 on: April 03, 2005, 10:36:51 PM »

Barry,
Your last post brings up valid concerns regarding the evaluation and rating of  microphone cables.
Barry Hufker wrote on Sun, 03 April 2005 16:34


To truly be any kind of believable evaluation, the test must be double blind....Only then when listening to various cables (in a double blind test) and making an assessment can anything be truly known, even if it can't be presently measured.  Anything else may be personally useful but not useful to us all.


Here I disagree, from experience.
I have partaken in double blind tests of audio gear over the years, and found them to be deficient.  Primarily because to me, the item under "double blind" test was as unfamiliar as the rest of the listening chain. (Often a chain which I found to be so deficient in resolution overall that it was impossible to separate out the culprit.

An example: I use a very old pair of 414 headphones for all of my work. If I gave that pair to another listener, the learning curve would be too steep for the listener to:
a. evaluate the double blind tested microphone
b. get used to the 'weird' sound of the headphones.
c. keep the two apart to evaluate confidently what he hears

To truly distinguish audible differences in a cable I think it makes as much if not more sense to do these tests with people who are thoroughly familiar with:  a. listening evaluations and b. their playback chain.

Quote:

I don't understand for instance what you mean by ..."Resolution".. "detail and clarity" I assume.  
 
I would define it similarly: High resolution to me is "amount of information in time".  Audiophiles correlate that to 'stage width' and 'depth', i.e. three dimensional psycho-acoustic effects from a two dimensional source.

Quote:

"Speed" may have something to do with transient response or slew?  

I am not able to correlate definitions of slew and transient response to what I hear:  it is often the case that a cable may have more speed at a certain frequency band than at another. How would you measure that in slew or transient terms, other than plotting a sine wave?

Quote:

"Congestion" is an emphasis on certain frequencies or is it a lack of clarity, which then would be resolution?


'Congestion' means a narrowing, or even collapse, of time-aligned processing of audio.
You get a complex passage/wave form, let's say a violin playing 1/64th notes over an orchestra at a fortissimo passage, accompanied by timpani:
How will the cable move the information along in time, without being overwhelmed by the complexity? Can it keep the various impulses, including  their relative volumes, apart, or does it smear it all together to an ugly mush?

The upper mid range processing of a cable is the canary in the coal mine here:
Bad cables (a qualitative verdict, not a matter of taste) will get harsh and hard under these circumstances. Good cables will stay with the music, more or less. No feature of a cable is more important to me than the above, because I correlate the level of listening fatigue or emotional attention to this feature.

Quote:

While I think a genuine double blind test should be done, I wonder here and now if any kind of consensus could be reached as to which audio cable is "best."  


Cannot answer that question; that's why I started the thread.

So far  I have found better cables through two methods:

1. I listen to every cable a manufacturer or colleague sends me, regardless whether it costs 50 cents/ft or $500/ft.  I will prioritize a cable test if I respect the source (i.e. someone whose audio tastes I know and respect.)

2. I never read the literature that comes with the cable before
I listen to it. I also categorically disregard any advertisement and any endorsement by any audio professional, regardless of his accomplishment in the business.

Quote:

 My guess is that we can't reach a consensus as to which is best, just as we couldn't with a microphone.

Here is a radical thought I believe in:
Yes, we can, and often do: As an example, a consensus of professionals  thinks highly of Tim de Paravicini's products.

But so far we mostly proceed to better audio components, even rankings, by just networking with experienced listeners and sharing what they experience.

But that is why I started the thread: Could there be more objective methods of honing in on the quality of microphone cables?  Testing methods that not only sound reasonable and agreeable, but can actually be realized by busy professionals without grinding lives to a halt or breaking the bank?
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Klaus Heyne
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Barry Hufker

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Re: Microphone Cables - An Intelligent Discussion
« Reply #16 on: April 03, 2005, 11:18:39 PM »

Klaus,

Thank you for answering.  I now more fully understand what you are saying when you mention the terms you used.

I understand your point about the problems with a double-blind test.  I can see where learning how a system sounds would take time.  But quite possibly then, this is another opportunity for Lynn Fuston.  His other demo CDs have been meticulous and it may be that a cable CD would provide an opportunity for everyone to hear the differences over their own systems.  And even if one can't say undeniably that a cable is "better" based on the CD example, at least it should point towards cables one could borrow/purchase/test while experimenting at home.

While I agree that Tim de Paravicini's work is good (and that a "consensus of professionals" might agree), would everyone agree his work is *best*?  I think one can get professionals to put gear into a "top tier" (such as Neumann, Schoeps, etc. for microphones), and I am sure the same can be done with microphone cables.  But how does one determine best?

Even as you listen to cables to find ones you like, and even given William's point about the acceptance of anecdotal evidence, the result then is nothing more than personal preference with no proof of best.  To me it is just like choosing a microphone, preamp, recorder etc. because it sounds pleasing rather than this combination is a proven *best*.

This to me then is how this discussion will end too.  People make artistic choices as to what, in their artistic judgment, sounds "best."  But another artist may prefer another *best*.

OK, having beaten that horse to death (and well into the next life), let me add a new angle here as I try to reach beyond my previous suggestions as to what makes a superior cable.

I have known for some years that it is standard practice (or at least has been standard practice before fiber optics), that AT&T used a puse method to find a break in extremely long telephone lines.  The method as I understand it was to initiate a pulse, then time how long it took for the pulse to "echo" and return.  That time told them at which distance the line was broken.

My new thought then is this: given the above technique, does every wire do this? Does every wire do this when it is properly terminated at some input?  And if it does indeed "echo" no matter how it is connected, then what effect does this "echo" have on the perceived sound of the moment?

Can anybody elaborate on this point or dismiss it?

Thanks!

Barry

And I appreciate you guys putting up with my ramblings!



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3D Audio

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Re: Microphone Cables - An Intelligent Discussion
« Reply #17 on: April 04, 2005, 12:55:00 AM »

Barry Hufker wrote on Mon, 04 April 2005 04:18

Klaus,

Thank you for answering.  I now more fully understand what you are saying when you mention the terms you used.

I understand your point about the problems with a double-blind test.  I can see where learning how a system sounds would take time.  But quite possibly then, this is another opportunity for Lynn Fuston.  His other demo CDs have been meticulous and it may be that a cable CD would provide an opportunity for everyone to hear the differences over their own systems.  And even if one can't say undeniably that a cable is "better" based on the CD example, at least it should point towards cables one could borrow/purchase/test while experimenting at home.



Thanks, Klaus, for bringing up this topic. It is one that I have steered clear of to date. Thanks to Barry for using the word "meticulous." Others have used different words, not all flattering.

I have been quite interested in performing a true double blind test under critical conditions to see what differences are perceived when the listener has no awareness of the signal path's identity or brand.

I am very curious to hear strictly-regimented testing that anyone has done and evaluate the results for myself. Barring anyone else coming forward with those recordings, it may be time for a "Cable CD."
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Gunnar Hellquist

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Re: Microphone Cables - An Intelligent Discussion
« Reply #18 on: April 04, 2005, 02:22:23 AM »

Barry Hufker wrote on Mon, 04 April 2005 05:18

I have known for some years that it is standard practice (or at least has been standard practice before fiber optics), that AT&T used a puse method to find a break in extremely long telephone lines.  The method as I understand it was to initiate a pulse, then time how long it took for the pulse to "echo" and return.  That time told them at which distance the line was broken.

My new thought then is this: given the above technique, does every wire do this? Does every wire do this when it is properly terminated at some input?  And if it does indeed "echo" no matter how it is connected, then what effect does this "echo" have on the perceived sound of the moment?

Can anybody elaborate on this point or dismiss it?




Yes,  
    both theory and practice agree that any change in the cable will reflect a pulse. There are special measurement instruments used in places where you have long runs of cables. One example is in aeroplane service, another is long distance cables. I see it used by the local electrical company searching for faults in ground cables as well.

In general (you should not really generalize, but still), the reflection of a healthy cable is more influential in higher frequencys, say a few Megahertz. If you go up to Gigaherz frequencys designing around this effect becomes a major issue.

The standard way to handle the problem in audio level signals is to have a low output impedance and a medium input impedance. In this way a pulse beeing reflected will be attenuated heavily by the low output impedance. The low output impedance has other positive effects as well. In general this is not an issue for audio level signals, at least not on the scale of things we are working on in a studio setting.

For word-clock cables the solution is a little different. But to keep things short I will stay out of that here. Suffice to say that you should terminate the cable.

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Gunnar Hellquist
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Barry Hufker

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Re: Microphone Cables - An Intelligent Discussion
« Reply #19 on: April 04, 2005, 09:40:24 AM »

Gunnar,

Many thanks for elaborating on the information about pulses and for clarifying the issue.

Barry
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wwittman

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Re: Microphone Cables - An Intelligent Discussion
« Reply #20 on: April 04, 2005, 09:42:13 AM »

Perhaps I'm missing something (wouldn't be the first time) but I seem to detect some discrepancy int he way the phrase "double blind" is being used.

In medical testing, double blind refers to niether the patient NOR the doctor knowing who is given the drug and who the placebo.

So neither the subject nor the tester can introduce a subtle prejudice or expecation of results.

In Klaus's example, he could certainly listen to his headphones that HE knows well and yet still have an assistant set up and A-B switcher with the A and B cables selected randomly and "blindly" by the assistant.. so that no one knows which is A dn which is B until afterward.
That's effectively double blind even WITH your quirky favourite phones.

I usually have the assistant set up the test and then leave the room so I have no cues from him as to which is which.
Effectively blind enough.
But I still listen on speakers I know well and a desk I know well and in a room I know well and so on...
otherwise, as Klaus suggests there can be too many variables.

but I know Lynn has agreed as well that thsoe FIRST impressions upon throwing the A-B switch count for a lot.

now double deaf testing is another matter entirely.
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William Wittman
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Barry Hufker

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Re: Microphone Cables - An Intelligent Discussion
« Reply #21 on: April 04, 2005, 09:53:45 AM »

William,

Yes, as you describe it, double blind testing means that neither the tester nor the "testee" (as opposed to "testes", which is another matter!)knows the identity of the object under test.

I have been searching the web for enlightment for surely it is to be found here ;>)  I came across this sight where the people assert they have found the things that make for a good or bad cable.  Any comments?

www.lessloss.com/cable_new.html

Barry
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Greg Youngman

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Re: Microphone Cables - An Intelligent Discussion
« Reply #22 on: April 04, 2005, 11:48:58 AM »

Well, here's what I think.

Microphone cabling does change the signal.  The laws of physics mandate it.  The length at which that starts to happen is the mystery to me.  The conductor material, gauge of the conductor, insulation, resistance, capacitance, inductance and shielding all play a part.  The longer the cable, the more these play a part.

A 1000’ run of different brands are going to change the signal differently.  But, I doubt you’d see/hear any difference between 1’ runs of different brands.

Then there's the "skin effect" controversy.  The movement of electrons through the cross section of a conductor is uniform when a direct current is applied to the conductor.  However, when an alternating current is applied, the phenomenon known as self-induction takes over, retarding the free movement of electrons in the center of the conductor.  As the frequency of the applied current is increased, more electrons flow on the surface of the wire. Skin effect is the tendency for high-frequency currents to flow on the surface of a conductor.  Skin effect, then, reduces the effective cross-sectional area of a conductor as frequency increases, and, because resistance is inversely proportional to the cross-sectional area, the resistance increases with increased frequency.  This increased resistance results in increased power losses as frequency increases.  For audio purposes, the key here is frequency.  Skin effect becomes a concern at radio frequencies (RF) as with a transmitting antenna.  At audio frequencies it's a moot point.  


I have never done a serious scientific study of different brands or designs of cable, but I have noticed an audible difference in brands.

The two brands that I have noticed the least amount of change are Gotham GAC 3 and Belden 8413.
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Klaus Heyne

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Re: Microphone Cables - An Intelligent Discussion
« Reply #23 on: April 04, 2005, 02:29:23 PM »

GY (Please insert your real name into your post- Ground Rules!) writes:
Quote:

...A 1000' run of different brands is going to change the signal differently.  But, I doubt you'd see/hear any difference between 1' runs of different brands


That's where logic gets in the way of listening. I would reason like you, but found otherwise:

Change the 2" wire from the capsule to the head board of a condenser mic (super high impedance), and tell me it does not matter!

Or change the 3" audio wiring inside the power supply (low impedance) from solid core junk to something a bit more audiophile, and tell me it does not matter!

Lynn writes:
Quote:

I have been quite interested in performing a true double blind test under critical conditions to see what differences are perceived when the listener has no awareness of the signal path's identity or brand.


You still will need to address the "familiarity" problem of the signal chain for every tester involved. Otherwise the tests will at best yield "I hear a difference", but no reliable and usable subjective qualitative analysis beyond that.

Barry wrote:
Quote:

But quite possibly then, this is another opportunity for Lynn Fuston. His other demo CDs have been meticulous


The devil is in the details, especially in audio testing.
I am not so sure that the "meticulousness" of Lynn's test set up included addressing issues which would be vital for my accepting the results as valid for a testing methodology.

His mic comparison CD, for example:
Were the mics used with original interconnect cables?
In what general state of originality (or operational health) were the vintage mics tested?  In this regard, were vintage mic experts consulted to verify the state? Was the verdict of one vintage mic expert double checked by the verdict of a second, independent expert?  Did the experts agree what component changes in the mic systems would result in audible changes large enough to disqualify a vintage mic as representative for its model?
Quote:

it may be that a cable CD would provide an opportunity for everyone to hear the differences over their own systems.

I am skeptical: Cable differences are subtle. I doubt audible impressions of a single use cable application would survive the transfer to a commercially duplicated 16 bit/44.1khz CD intact.

One would need to accumulate cable usage in such a way that every instrument and vocalist in a multi-channel set up would use the same cable, so it adds up to usage as encountered in a commercial studio.

Quote:

While I agree that Tim de Paravicini's work is good (and that a "consensus of professionals" might agree), would everyone agree his work is *best*? ..How does one determine best (in a cable)?


I would be very happy to find a consensus of the United Taste Buds of the World to at least eliminate the very worst cables (some of them very well known industry leaders!) from the free ride they have gotten so far in the market place.

Imagine how much better recordings could sound all over the world by doing just that!


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Klaus Heyne
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Barry Hufker

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Re: Microphone Cables - An Intelligent Discussion
« Reply #24 on: April 04, 2005, 03:55:51 PM »

Thanks to Steve Fuller, a truly talented and informed engineer, I have been told of a reference to our topic.  It is in Chapter 32, page 1099 of Glen Ballou's "Handbook for Sound Engineers."  Bill Whitaker (president of Jensen Transormer) wrote (and I am paraphrasing now as I don't have that edition with me) that [high capacitance cables are detrimental not only to high frequency response but also can present a dead short to a microphone amplifier during a transient.]  With this criteria in mind, Bill found Belden 8241F to be the best cable.

Barry
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David Satz

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Re: Microphone Cables - An Intelligent Discussion
« Reply #25 on: April 04, 2005, 04:21:16 PM »

Klaus, you wrote: 'Change the 2" wire from the capsule to the head board of a condenser mic (super high impedance), and tell me it does not matter!' Point taken--but it should be no surprise to anyone. Very high-impedance circuits are a different world from low-impedance microphone outputs. In this specialized area a design engineer has to consider aspects of everyday components which aren't normally significant. The AES Journal ran a paper last year on the -10 dB pads in many condenser microphones and the increased distortion which they can cause--introducing stray capacitance as an unintended side effect of the switch design. It's almost as if the capsule end of a condenser microphone was a miniature haunted house.

With low-impedance signal sources and normal high-impedance loads at audio frequencies (e.g. condenser microphones and preamps), things become quite a bit simpler. The parameters of resistance, capacitance, inductance are on general good behavior, and any differences between what you put into a cable and what you get out of its other end can be predicted rather well. And nicest of all, the calculations match with what people hear and vice versa. I don't know of any controlled study of analog audio cable in which any listener could repeatably distinguish between cables whose conventional parameters didn't account for what was being heard; do you?

A little Ohm's Law still goes a long, long way in audio.

--best regards

P.S.: Dan Lavry's forum is weeks ahead of us on this--people here might want to read what he and others have been saying over there (though watch out for trolls). Some of it is in the thread on the "High-frequency transients fallacy" and some is in the thread "On Skin Effect in Cables".
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3D Audio

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Re: Microphone Cables - An Intelligent Discussion
« Reply #26 on: April 04, 2005, 05:06:08 PM »

Klaus Heyne wrote on Mon, 04 April 2005 19:29

GY (Please insert your real name into your post- Ground Rules!) writes:
Quote:

...A 1000' run of different brands is going to change the signal differently.  But, I doubt you'd see/hear any difference between 1' runs of different brands


Lynn writes:
Quote:

I have been quite interested in performing a true double blind test under critical conditions to see what differences are perceived when the listener has no awareness of the signal path's identity or brand.


You still will need to address the "familiarity" problem of the signal chain for every tester involved. Otherwise the tests will at best yield "I hear a difference", but no reliable and usable subjective qualitative analysis beyond that.

Barry wrote:
Quote:

But quite possibly then, this is another opportunity for Lynn Fuston. His other demo CDs have been meticulous


The devil is in the details, especially in audio testing.
I am not so sure that the "meticulousness" of Lynn's test set up included addressing issues which would be vital for my accepting the results as valid for a testing methodology.

His mic comparison CD, for example:
Were the mics used with original interconnect cables?
In what general state of originality (or operational health) were the vintage mics tested?  In this regard, were vintage mic experts consulted to verify the state? Was the verdict of one vintage mic expert double checked by the verdict of a second, independent expert?  Did the experts agree what component changes in the mic systems would result in audible changes large enough to disqualify a vintage mic as representative for its model?



"Uncle!"

OK, Klaus. Your obsessive compulsiveness trumps mine. (And that's not easy to do!)
(Those who are concerned about me would be positively disturbed by you.)

There are a few thousand variables in a test like I conducted. I decided which were important to me and proceeded with that plan. And like everyone else who's ever done anything like this, I learned a lot in the process. What to do and what not to do.

I never intended or implied that the vintage mics on the shootout were "the gold standard" example of that particular mic. They were ones that I believed were representative, either by my own experience or through the recommendations of people like Bill Bradley, whose 251 and U47 we used. I don't know about the internal components or originality of the cabling.

My comparison compared specific mics, this U87 to this U67 to this U87ai. This 251 to that 251 clone. I even think I have a list of the serial numbers of the specific mics that we used.
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Klaus Heyne

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Re: Microphone Cables - An Intelligent Discussion
« Reply #27 on: April 04, 2005, 05:52:33 PM »

Quote:


"Uncle!"

OK, Klaus. Your obsessive compulsiveness trumps mine...
There are a few thousand variables in a test like I conducted. I decided which were important to me and proceeded with that plan....
I never intended or implied that the vintage mics on the shootout were "the gold standard" example of that particular mic. They were ones that I believed were representative, either by my own experience or through the recommendations of people like Bill Bradley, whose 251 and U47 we used. ...

Lynn,
I would not regard an inquiry into the originality of a vintage mic that is part of a comprehensive comparison test excessive.

After all, listeners may indeed make a purchasing decision based on preliminaries heard on your CD (of course only fools buy a vintage mic without listening to it)

I hope you would agree that a vintage mic whose sound shaping components may have been removed and substituted with non-stock components will not be very representative of the model.

So, assuring a mic's stock componentry in good working condition would fall into my criertia of "musts" not "gold standard" of a mic comparison test.

Quote:

I learned a lot in the process. What to do and what not to do.


I am curious to hear what you have learned. You spent, I am sure, an extraordinate amout of time on the process. Please share it, if you can. Maybe some of it is also adaptable for cable comparisons?

Kind regards,
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Klaus Heyne
German Masterworks
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3D Audio

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Re: Microphone Cables - An Intelligent Discussion
« Reply #28 on: April 04, 2005, 06:26:23 PM »

Klaus Heyne wrote on Mon, 04 April 2005 22:52

 I am curious to hear what you have learned. You spent, I am sure, an extraordinate amout of time on the process. Please share it, if you can. Maybe some of it is also adaptable for cable comparisons?

Kind regards,


I like that word "extraordinate." Sort of a combination of extraordinary (Def: Highly exceptional; remarkable), which it was, and inordinate (def: Exceeding reasonable limits), which it most certainly was.

I have several threads entitled "What Lynn Learned" at 3dB, where most of the critique and feedback of these projects has been discussed. Let me see if there is a thread like that for the Mic CD. It may be older than the current archives for this software rev. I'll report back on what I find.
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Klaus Heyne

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Re: Microphone Cables - An Intelligent Discussion
« Reply #29 on: April 04, 2005, 06:31:24 PM »

David Satz wrote on Mon, 04 April 2005 13:21


...Dan Lavry's forum is a few weeks ahead of us on this issue--people here might want to read what he and others have been saying over there (though watch out for trolls). Some of it is in the thread on the "High-frequency transients fallacy"


David, I got as far as page one, then got bored. (I don't believe that I ever used the term 'high frequency transient response' here. Barry Hufker mentioned 'transient response' in passing, but did not elaborate.)

Please tell me how his thread can help me select better cables for microphones, by what ever method. I have not found one yet.

I am of course aware that my example of different sounding 2 inch wires in a capsule head is not directly applicable to microphone cables, due to the super high impedance.

But here is the connection: I am unable to measure anything on a two inch wire that would clue me in on its sound. Try to distinguish capacitances from one 2" wire to the next!  
There is no capacitance tester I know which can be reliably employed to measure beyond two digits after the period (the limit of mine) Statically, outside of the circuit, they measure the same, so why bother?

The same problem I have with static testing  of mic cables- If it was as easy as you claim - pick the cable with the lowest everything-  we would be done.
But I have not found that for example the lowest conductor-to-conductor or conductor-to-shield capacitance per 1000ft are any indication for high audio quality, certainly  not in cables measuring 1/50th of that length- the typical typical for a mic cable.

This side of grossly high capacitances, measured capacitances in cables have no correlation to cable quality, I have found.  But maybe other, so far neglected criteria may give a clue?
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Klaus Heyne
German Masterworks
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