This is one of the most controversial topics in hi-fi so i don’t expect that you will get any helpful answer here.
Personally i don’t care about cable burn-in because my brain, my state of mind etc. influence the sound of a system much more than any not explicable science in cable burn-in. Psychoacoustics is an important part of any hi-fi but is ignored by many.
When a cable manufacturer advises 100 hours of burn-in i read: allow your brain about 100 hours to get used to the small differences and then evaluate if you like it.
Or get used to it and not reject it as a direct comparison may cause you to. And that of course may apply to far more than cables - though some things undoubtedly can change with use especialy where physical flexing is involved, or significant temperature change when in use.
I won’t offer theories as I have none (and have little regard for some theories I’ve read regarding cables burning in), however my curiosity was piqued because yours seemed to offer closer to objective observation than most. (And just as you weren’t trying to change opinion, I wasn’t refuting your observation but seeking clarity as to circumstances and how objective it might be.)
I’ve been reading hifi forums for long enough to know that there is no hifi ditch worth dying in when you could be enjoying listening to music. I am sometimes mildly amused that religious discussions are banned on this forum but that discussions of cables etc. are, in principle, fine, when the latter can easily become just as divisive and dogmatic as the former.
But I digress:
A physical process which will happen in a stranded cable as it has an AC signal passed through it is that the individual strands will attract and not-attract each other with every AC cycle. If the cable has been left with stresses in it as a result of the manufacturing process, this cycling of attracting and not-attracting could reduce these stresses which, in turn, could change the electrical characteristics of the cable. This, in turn, could be audible.
Note to argumentative readers: I have very intentionally couched that explanation very conditionally. I have also not ventured a personal opinion on the matter. Bear that in mind before you waste your time and effort shouting at me.
I have here some audioquest power, speaker, and interconnect cables, I do not know for sure the effects of burn in, but in some cases the sensation of losing some initial harshness come to my mind.
But the differences are not night and day, so just plug it in and never worry about it if they result out of the box.
On the other side like amplifiers the burnin can make a huge difference over the first week or two.
Cable burn in is absolutely true I’m surprised it is even being discussed now
As Niels Bohr showed in his seminal work, electrons, when passing through a conductor, say copper wire, they are met by resistance. If the copper molecule does not know the electron he says “wait”. “Who are you”. The electron has to explain until the copper molecule says ok. Delaying transmission. But after some months the wire just lets the electrons pass. Most definitely. And yes, really expensive Fraim racks will shorten break in time. But not to zero. You also need a separate electricity generator for your stereo. Don’t even get me going on pumping argon gas into your listening room
I am becoming more convinced that fresh solder joints need about 6-8 hours to sound right… I have adjusted my treble level recently, this involves unsoldering one resistor and replacing for another. All of which are considered to be “run in” but for some reason this fresh solder joint seems to need a little time to sound smooth again. Might just be me but it seems to be the same every time. Weird. I am definitely of the opinion that cables sound different but not sure about an old for new of the same type… never tried that.
I should resist the temptation to jump into the snake pit.
But the thing that strikes me about this topic is a presumption thatve observer’s hearing is a constant. Shouldn’t all observations come with a disclaimer that one’s ears might have been having an off day? Or for that matter that the listening environment was somehow different? (Humidity, temperature, background noise, etc.)
I am not satisfied that the claim “it sounded different” can be attributed to one factor (such as the cable) and dismissing these other variables.
