Burn in vs perception

What is the basis for the belief that a mechanical device, speakers especially, would change over time? If they require break in for the first 200 hours for optimal sound, and it’s interesting that it’s always a round number in the 100’s, what is preventing it from continuing to change over the next few hundred hours and so on, continuing to change to failure? Is there really a “bathtub” curve for flexion of the suspension material, a’la MTBF? 

This isn’t like breaking in an engine in which the bearing surfaces are getting smoother and hence experiencing less friction improving performance. This is a flexible material that is being flexed and stretched. A change in those properties would seem to require a chemical or molecular change, not simply usage. 

i believe the only thing that is “breaking in” is your perception. 

OCD Hi Fi Guy On Break In

I own a complex headphone with two different cells one dynamical the other one Electrostatic...

The dynamic cell come full blown after a warm-in period of 10 to 15 minutes...

The difference is not illusory...No one hallucinate each day at the same hour and only about deep bass and bass... 😊

Then if complex components need warm-in , it did not ask for great brain work to deduce that NEW component which had never worked BEFORE as a WHOLE may ask for an adjustment time which can be audible with some components more than with others ...This is called break-in...

And those "objectivist" claiming that this is  mere placebo or subjective impression of stupid audiophiles need to read about PERCEPTION and his relation to phenomenon, Cartesian dualism is dead , and some Illusions are more real and meaningful than some material object... Anyway break-in is a physical observed and probably measurable phenomenon ...

An immaterial perceived  rainbow is more powerful most of the times in his effect on us than a grain of sand...

«What if this grain of sand is in my eye?» --Groucho Marx 🤓

I have long believed it is your ears acclimating to the new sound.   In the case of speaker surrounds I believe that is valid but it is a short break in.   Is it even enough of a change to perceive?    Not sure about that. 

Example,   I just picked up an integrated amp.    I set it up in my main listening room.    First with my Forte and then with my Sonus Faber Concerto.   

The Forte sounded really good.  I switched to the Concerto.    Completely different presentation,   but it sounded good.   Thin compared to the Forte.    It took a while for my ears to accept the new sounds they were hearing.   Better ?  Worse?    No....just different 

A topic hotter than a cables and cones thread.  

If you haven't heard distinct changes in the sound of audio hardware from new to maturity you haven't purchased enough new hardware.