This scaped me and was not intentional, I apologize.
My apologies again.
I thought it was a point of pride of Naim owners to be a flat earther, ever since the famous review by the late Art Dudley in Stereophile many years ago.
In learning for this thread, I also read many posts by the most active members in the thread, and about your systems and CVs. I happened to remember a post by you referring to yourself as a flat earther, in a very funny way. But probably I am mistaken and it was another person.
But the above can not be an excuse, as cannot be an excuse that English is not my first language. If I am at risk of offending other people, I should be more careful.
In any case I have not decided the outcome of the experiment, I promise. I am one that cannot listen to a difference in cables (for directionality or burn-in). I do not know if it is because of my system (very modest), or my ears (very old) or just because burn-in does not exist. I want to discover an answer to this.
Very sorry, I will be more careful.
Doctors prescription:
Read cable burn in thread three times a day whilst burning in cables out of Naim units.
Whilst subjectively I have noticed changes in my perception of both headphones and IEM’s as well as differences in cables … the actual burning in of cables I’ve never really had the time to ascertain. Perhaps as both headphones and cables are new when i first purchase them so haven’t had the chance.
A perfectly good excuse, I reckon. No offense taken.
Personally if I had to read this thread 3 times per day, I would not be able to listen to music, more able to go to sleep.
Something I’ve never thought about before: is there such a thing as direction of current in a cable carrying only AC? I don’t think tgere is, unlike in a cable carrying DC, which with a pair of conductors connecting energy source to load has a flow of electrons in one direction in one wire and the other direction in the other.
If there is no direction of current in an AC carrying cable, which is what analogue audio cables are, then I can’t see how perceived difference in sound in with the cable different ways round can be anything to do with direction of wire extrusion.
Walk, don’t run!
Best wishes for a speedy and successful recovery
I suspect that the idea is that there may be some rectification effects in the cable (I have no idea how - except possibly at the terminations/solder joints) and this could affect the (AC) signal.
This would be much more important, and known about, in other applications.
I don’t understand why audio is considered to be so very different from any other signal…
I know people have suggested that, but if the AC signal was rectified to DC then I think there would be a very significant effect, notably silence and if with speaker cables a distinct possibility of bass driver burning out in a short space of time.
I am not convinced you can get partial rectification: if you put a diode in parallel with a solid wire the reverse current would just flow through the wire.
I must admit, I’m not sure how it would partially rectify the signal, but…
I see I have to be extra careful, but let’s be practical. Suggested procedure:
-
Get two identical cables (same manufacturer, same model, same length)
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Keep one unused, use the other in an audio system for 90 days (intensively)
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Measure for both cables the following parameters:
DC resistance
Inductance (at 1 kHz)
Capacitance (at 100 Hz, 1 kHz, 10 kHz and 20 kHz)
(Then if these parameters are not identical, there will be evidence that something has occurred, let’s call it burn-in) -
Measure an attenuation curve for both cables in dB / 20 Hz-20 kHz
(Then if these curves are not identical, there will be evidence that burn-in has occurred) -
Conduct the following experiment
Prepare two identical signal generators in opposite phase for each cable, connect to a common point (some resistances, etc. may be necessary to protect the circuit and generators)
Measure an attenuation curve in dB / 20 Hz-20 kHz
(Then if the curve is not flat, there will be evidence that burn-in has occurred)
Connect the common point to a loudspeaker
(Then if sound/noise can be perceived, there will be evidence that burn-in is audible)
THIS IS WHAT WE ARE DEBATING
Note: This experiment is designed to avoid influence of temperature, humidity and other bias -
Perform a crystallographic analysis of both cables
If the analysis provides evidence of changes in structure or other, we can conclude that using the cable for 90 days has modified the cable (and per the above experiment, the difference is audible)
Some details to be developed but I need to talk with an expert.
Please challenge the above and let me know what confirmation or subjective bias you can find.
For your comments and/or approval.
Edit: It is loudspeaker, not loadspeaker.
Of course with this procedure we are just starting, we will then debate how to extend this experiment to a general theory (if the group agrees that at least in one case there has been burn-in).
You don’t need to measure much (initially, at least) if you put an identical signal through both sets of wires (burned-in and not-burned-in), then invert one signal coming from one set of wires, and sum the two signals. If the result of the sum is zero (or sufficiently close) then you know that nothing is being changed in one set compared with the other.
Only if you get something significantly different from zero do you need to examine it further. And the waveform of the difference between the two might give you clues as to what to measure.
Also both cables would have to be measured beforehand to establish a baseline…
You need to do 3, 4 and 5 on both cables before burning one, to verify they are the same or note any differences. And all measurements alternating cables between each time to make them completely independent tests, to show the repeatability. (I know this isn’t enough for statistical assessment of repeatability, but should give a good idea. If there is significant difference between repeats of the same measurement, then maybe more needed and do a proper assessment.)
And again at end of the burn in of one, do three sets of all tests on both cables.
Yes this is point 5.
Useful to understand what two identical cables are and what we should consider a difference. I will add to the procedure.
Part of my conversation with the expert.
Yes - you are inverting before the cable, so if directionality is a factor, then it will be a confounding factor here. I’m not sure what you mean by connecting to a common point, but I was suggesting actually adding the two signals together (using suitable circuitry/amplifier - presumably a differential amplifier would do the job well) so that you can ensure that the impedances are matched etc. - and you can observe the shape of any signal that comes out (so you are not relying on the loudspeaker’s sensitivity to different frequencies and power, for instance).