I have heard broken-in demo Focal 806v speakers many times and on one trip to the store identified a pair of fresh out of the box demo speakers that sounded a bit harsh in comparison. Break-in for speakers is real in my experience.
I have a tube amplifier and it did improve with a break-in period and does require a little warm up to sound its best.
I believe that some burn-in is most likely beneficial to analog components, but struggle wrapping my mind around a scenario where burn-in could have an audible impact on a purely digital component.
The amount of perceived varience that I hear in my system is beyond anything that I could accept as a change from burn-in making it virtually impossible to identify any tiny change from burn-in.
I have Nordost Sort Kones under my SACD player and “think” they may have improved things a bit, but could never identify if someone were to remove them without my knowledge.
There are so many factors that impact the way we perceive a given listening session that I don’t think that burn-in on a purely digital component would ever be audible, especially with all of the engineering specifically aimed at perfecting the digital signal when one can build a fairly solid case that it’s just ones and zeros.
The fact that manufacturers recommend a break-in procedure can be based on objective fact in some instances and for others it’s just part of the “audiophile” culture where having a component that doesn’t require a break-in could automatically inferior. Plus, an extended listening period will most likely give the listener/customer time to adjust to any new sound (or perceived change in sound) with placebo to go with a new purchase likely to lead towards a happy customer.
