Some human minds seem less malleable than metals.
Sent with a small red hart.
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Is your an organization a member of the AESā¦ why not publish the results thereā¦ kind of the equivalent of the Lancet for the global audio scientific and engineering community ā¦ it would be be of far more relevance and weight than publishing in a Hi-Fi comic, and where much genuine research, development and assessment around audio in many of its fields are published.
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Thank you for the suggestion, to be considered.
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I guess one needs to be slightly carefulā¦ most things with some sort of chemical dielectric will change over timeā¦ there are few things that are completely inert.
To me the interest is with changing electrical properties over time, is the revelance and audibility within a system, ie in this use case source and load impedances and other factorsā¦
Ie the effect of change by a cable is going to, I suggest, depend on source and load impedance properties of connected devices.
I think in an audio test these aspects will need to be carefully considered and modelled to have a meaningful resultā¦
As I suggest earlier within the AES there has been occasional research into the affects of cables in audio systems in terms of sound quality (actually technically distortion)ā¦ and the only thing meaningful close to our case I have found and seen has been with loudspeaker cables, and that has been shown to be dependent on amplifier output impedance and the specific reactive elements of loudspeaker impedance.
Therefore more research into small signal conductors would be interesting.
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?
Are you referring to cables to assessā¦
I guess you should define your hypotheses first and characteristics of cables you want to explore along with any electrical audio distortion characteristicsā¦ one determined then select sample cables that you feel should be able to demonstrate these evaluation criteria.
As I said above I would be interested to see how you model the source and load impedance that the cable forms a circuit with so as to be representativeā¦ and indeed any variability against your defined criteria
Not really, I would like to demonstrate that all cables burn in. The first experiment will just be (if successfully demonstrates burn in) a small wedge in some minds.
I am thinking about interconnects because they seem easier to burn for 500 hours, without making my neighbors crazy.
Sure but I would have thought you need to set a reference to assess āburn inā from a point of view of audibility and connected electronics, otherwise surely this becomes meaningless from an audio / electrical perspectiveā¦ and we are back to square oneā¦
Ie is it mechanical, contact junction change, dielectric, metallic, system dependent etc etc.
Anyway I look forward to reading what you derive from an audio perspectiveā¦ but see if you can isolate mechanics and pressure contact (connection) variability which often do change over time audiblyā¦ and the latter could be affected by electrical current.
We will compare two cables, one new, one burned in.
They will be of same length, model and maker (and hopefully same production batch or at least purchasing batch).
We will build a Wheatstone bridge with two new cables and confirm the bridge is balanced with an oscilloscope.
Then we will burn in one cable 500 hours.
Then back to the bridge to measure again. If there are changes or asymmetries, we should be able to plot two different curves of dB attenuation in the 20 Hz to 20 kHz range (before and after burn in).
We will use a high quality wave generator and high quality oscilloscope.
With this experiment, we may demonstrate that burn in exists as a process (for the tested cable). Then we may test other cables for a general theory.
If we are successful and we find differences higher than 0,5 dB, we may demonstrate that burn in is audible using an audio amplifier in place of the wave generator and a speaker (or headphones) in place of the oscilloscope.
Easy.
To help everyone to visualize better the experimentā¦
Okā¦ and of course the Wheatstone bridge is primarily for resistances, and you will need to work with impedances for audio and measure the reactive elements separately across the pass bandā¦ I think the Wheatstone bridge will only show resultant impedance rather than the specific inductive and capacitive elementsā¦ but I suspect you may have a nifty way of dealing with that.
I would be surprised if resistance changes with burnin (other than extreme cases), but reactive elements associated with any dielectric just might.
Could I suggest a high bandwidth square wave generator is used as a source impedance and a known harmonic rich source, into a representative source load (donāt forget that) and you use a spectrum analyzer to compare before and afterā¦ that could be quite illuminating and could be audibly relevant.
You could of course use a pink noise generator source, if you have oneā¦ which would be preferableā¦ but more specialists perhaps.
Also easier with interconnects is that the choice of load, whether a power amp or dummy, is easy because there isnāt a great deal of variability between different power amps, whereas the load characteristics of different speakers can be much more variable.
On the other hand, given the much greater voltage and current (typically maybe 16000x the power) in speaker cables, with the likelihood of the signal causing change therefore much greater, wouldnāt it be better to start with speaker cables if you want to have the best chance of detectable change? You could use a dummy load, and thus completely avoid sound leakage.
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Variations on the Wheatstone bridge can be used to measure capacitance, inductance, impedance and other quantities, such as the amount of combustible gases in a sample, with an explosimeter.
Should suffice to us.
Ok, as I said I thought you would have way of dealing with that 
. obviously that is frequency dependentā¦ so I guess you will be carefully tracking that.
So you will be precisely tracking capacitance and inductance across the pass band across between the pre burn in and post burn in cable?
Do shareā¦
It would be interesting to compare with spectrum Analyzer output of before and after.
Please note that all the variability of amplifiers and speakers is taken away from this experiment.
I make a note to test (later on and if we demonstrate burn in) directionality in speaker cables.
This will be even more fun, as Naim has engineers listening to cables for directionality, and if we demonstrate that is not possible we will probably be banned from this forum.
I will follow your suggestions. Will send maker, model and calibration certificates of equipment used for your perusal.
Thanksā¦ but I am no standards house
Thanks for your efforts here, i hope it shows something interesting one way or another.
Exactly what we are going to do.
Excuse me a personal question: Are you a believer or a non-believer?
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I am an engineerā¦ā¦
So my focus here is no false cause and effects by not fully defining or controlling the evaluation environmentā¦ but very interested to see any relevant outcome for audio between defined source and load impedance.
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Maybe a title for a thread!
In my case I am neither, rather I have a healthy scepticism about such things, particularly when promulgated by manufacturers who have a vested interest in people not rejecting something instead using until their ears get used to it. I canāt conceive of a feasible explanation for cable change of any significance, especially in low level signal cables (interconnects), though I accept that not everything is known about everything.
Iāve never been aware of changes in cables over time, but then I know my ears are not constant reference devices and lots of things donāt sound precisely the same all the time, while I know that memory of sound is also not precise, so I donāt listen for differences over time. Leaving aside considerations of possible psychological influence in observations, As Iāve observed more than once here, virtually all talk of cable burn-in is based on memory not direct comparison,. I was therefore particularly interested when the OP started this thread, describing a direct comparison, albeit no guarantee tgat the new and old cables were identical to start with.
So for that to lead to a range of electrical, physical and listening tests designed carefully and conducted under controlled conditions to try to assess whether there is a measurable or/and audible change after burn-in is rather exciting!
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