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Discussion Starter · #1 ·
I am starting out this thread by copying a few choice quotes from the Bruce Candy, Halcro, Special Guest thread over at the AVS Special Guests forum.

This is because often folks, especially engineeers, harp on that the cable can't make a difference in the sound. And many audio engineers who design equipment frankly don't want to get into this debate, even as Special Guests - and I don't blame them, because they want their focus to be on their products. But Bruce Candy is a Physicist, and a fantastic designer of audio equipment - any ever having heard his Halcro amps would know that. They've won the Best of CES award, and of course they were used in the 2001 DTS room setup by Chris Stephens and other Ultimate Entertainment folks (back when Chris worked for Ultimate Entertainment, Chris has been with his own company for some time now).

So what Bruce says re cables should be interesting and help start a productive discussion.
 

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Hi QQQ,


I am sorry, I have only just spotted your short inquiry.


I presume the underlying question is, am I an engineer. No I am not, I am a physicist (and applied mathematician).


I started off as an academic, then moved into the world of business, which I have found most exhilarating. I did research in several disciplines, such as molecular physics, atmospheric physics and the detection of light. (Whilst I was still studying for a PhD the American Institute of Physics made the highly unusual step of requesting me to write an "Invited review article," something usually restricted only to very well established academics.The paper was published in J. Sci. Instrum.) However, I have spent most of my working (and school!) life designing electronic circuitry, in the fields of medical, R.F., wideband, high power switching, metal detection, and of course, audio. Many years ago I used to run a course called "Electronics" for final year electronic engineers at a local university.


Thanks.
 

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Hi Bruce:


Thank you for your answer to my question as well as the fascinating and thorough answers to everyone elses.


Could you please comment on whether you believe in audible differences between esoteric cables (assuming NO purposeful filtering and basic good design) or whether normal DECENT quality 12 AWG speaker cable is adequate for using with your power amplifiers.


Thank You
 

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Discussion Starter · #4 ·
Bruce, as you are our GUEST, and you design and manufacture high end components, you DO NOT have to get into the cable questions, unless of course you feel comfortable answering them to any extent. And I will caution that I and other audiophiles, although we do feel that cables can make a difference, that there are many games in the cable industry, and too often cables can be tone controls and change the sound - its so much

easier to follow reasonable ground rules, have accurate sounding components in the first place (especially HALCRO!!!), then have interconnects and speaker cables which do their best to accurately deliver the signal without skewing frequency response (acting as a tone control) - inotherwards, cabling which as closely as possible, for a reasonable price, communicates the original signal without deviations or alterations. OF course, QQQ's question is a good one, just one that often manufacturers would rather stay away from controversies concerning cabling. But if you feel comfortable commenting, please do, and if you have any recommendations of cables which you feel go particularly well with your amplifiers, please feel free to educate us re which cables and why? Thanks.
 

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Thanks for the advice, Steve.


First, QQQ, I live mainly in Australia, but also in France.


Second, I have always used my own cables- thick Litz wire, and never actually critically listened to different cables.


I can say for certain, that all the "scientific" papers I have read written on explaining sonic differences are quite seriously flawed. That, of course, does not mean there are no sonic differences, it only says something about the authors.


As a physicist, can I think of any mechanism that will cause sonic differences, beside the well known fact that high impedance cables will result in a more coloured sound (as Steve points out)?


Actually, yes! Three mechanisms, all virtually unconsidered: 1 problems with connectors, 2 dielectric absorption, 3 piezo electric effect.


I have had a great deal of experience of these sources in state-of-the-art metal detectors.


Connectors.


I'm sure it will amaze most people to learn that the differences between various connectors are extremely pronounced!! In fact most are so noisy and distorted, that they are quite unusable in a metal detector! Most surprising of all, the costs are not correlated with performance. There are several mechanisms which cause the problems. The two most serious are:


A. Variable contact resistance.

This is highly variable between different connectors and also highly troublesome in metal detectors. It is quite possible that this may be a problem with some loudspeaker cable's connectors. This is particularly so at the loudspeaker, where the connectors are subject to a history of vibration. In addition, I have noticed that some (small signal) interconnects have loose fits, especially some RCA plug earths. It is likely that this will cause serious problems.


B. Dielectric absorption in connectors.

If this is present in interconnects which are driven by relatively high impedance sources, which are in fact relatively common, this may cause sonic effects. Again, this is highly variable between different connectors. It is most likely that this will be most pronounced in some XLR units. It will probably surprise, that often the worst connectors in this regard are military grade devices. As a result, in the land-mine clearing detectors that I have designed, I have also specified the design of the military grade connectors.



Cable dielectric.

Both piezo electric effect and dielectric absorption may cause sonic problems if present in interconnects which are driven by relatively high impedance sources. Piezo effects will only be problematic if the sound intensity near the cable is significant. The differences between cable in the degree of both piezo electric effect and dielectric absorption is highly variable. Worse still, it is variable from one batch to the next. Recycled dielectric is often appalling in this regard. The only commonly available dielectric guaranteed to be free of piezo effect is high quality microphone cable and teflon; and free of dielectric absorption is r.f. or microwave cable, (which is often teflon).


Sonically, variable contact resistance, especially if subject to loudspeaker vibration, may cause distortion, as will piezo electric effects. Dielectric absorption will cause tonal effects.


So yes, I can think of some mechanisms that may cause sonic effects associated with cables under some circumstances. No doubt there may be effects that I have not considered.


Anyone with other ideas??


I hope you find this interesting and hopefully, challenging!
 

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Discussion Starter · #6 ·
Hasn't what Bruce has given us explains why different cables can sound different with different components???


The problem with cabling remains that all sorts of technical explanations that most of us can't understand are often given by cable companies.

And probably all too often cables serve as tone controls rather than accurately delivering as much of the original signal as possible. And of course cabling pricing structure, all too often WAY more than typical capitalistic price models might normally justify.


Lets hear from other folks about objective characteristics of cables that will lead to sonic differences. Thanks.
 
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