Burn in vs perception

Audiophile: 

   "So I've done what was recommended and let this cable burn in for 300 hours, but it still sounds the same.  I'd like to return it for a refund."

Salesman:

   "I'm sorry but the return for refund period has lapsed.  I'd be happy to buy them back from you for say, 10 cents on the dollar?"

Tube burn in tends to be very short in comparison to the solid state components and wires. Ten to twenty hours for tubes. 

I won't argue as I am but a simple idiot. 

I will say this though. If anyone really wants an answer to this. I found it amazingly simple. Build yourself a headphone amp. Say something simple like a Bottlehead Crack. If you don't notice a huge night and day type difference from hour 1 and hour 20. I don't know what to say. I will never say I have a great ear. I can hear but also have some hearing issues. 

After that experience I no longer argue. In my experience I can't deny, it is real. 

Cheers.

J.F.

"Hi, guys....my name is Jerry and I am a....*non-pg pause*....

*sigh*....a thin-skinned pansy..."

*snickering in the crowd, someone laughs..*

"...*softly*...byte me...no, don't....f'n vampwire...*snort*...."

Physically, yes.  I bruise if you look at me hard....between the blood thinners, diuretics, heart meds, Symbicort, and the self-indulgent stuff that allows me to be

1) Vertical
2) Able to still wander about under relative control, but yet able to clip Something that will make me 'leak' red 'hydraulic fluid' like I've been knifed..
3)...but clots faster still enough to bother my cardiologist(s).
4)...and 'get a verbal slam' at punks 25ish% of my age...

I refuse to 'age gracefully'...deal. ;)

Speakers are mechanical: Full Stop.

Anything that exhibits motion of some form can have a form of 'break-in'

Tubes, ttables, carts, even a CD...moves.  The amount varies, so the 'break-in'/'warm-up' cycle(s) ought to be considered subject to Something....

Butt, mine or yours...since we exhibit the most 'motion'....within the space, away from a space (esp. your listening one...or however many...), and are subject to 'adjustments' more than anything else in your chain of audio extravagance..or not..

The biggest warm-up/cool-down is our perceptions and expectations of what we expect to hear immediately (if not sooner) falls to that same olde wetware we haul about.

Case in point; personal:

If I'm away from my 'pyle' for awhile, it takes me a day or so to re-adjust, recalibrate, remember (*huh?*L*)....basically reboot self.

If absent long enough, all has gotten shut down.
It likely takes as long as me for 'it' to return to 'normal'...

...whatever that was.

YRMV....and likely do, to your whatever it was... ;)

MHO, but enjoy self, anyway, J