What is "break in" and what difference does it make? In amps? Preamps? Speakers? More?

Have you tried candling your ears recently? 🕯

Is there a difference in what one hears when it comes to speaker break-in vs. component break-in?

Not really. All start out with whatever fundamental character they have, but thin and etched or grainy, and then over time fill in and round out becoming more palpably real. To whatever extent they are capable of doing this. The differences are only in the details. The over-arching fact of improving with use is the same regardless of whether we are talking about a speaker or cable or component, or even a part like a fuse, cap, diode, or transformer. They are all the same.

Are there levels (quality) where break-in makes no difference?

No.

There are levels where some are run in before shipping. But no one is going to run anything 24/7 for 30 days- and even if they did it would still go through a mini break-in when first hooked up after being banged around in a cold shipping container for who knows how long. Just like every night the gear you had turned off during the day takes a while to warm up and sound its best, so everything brand new goes through the same process, only more so.

Hard to believe after all these years there are still people questioning this. I’m not talking about the OP, who we can excuse for being new. I’m talking about these others still pretending what is staring them right in the face is not really there. What is wrong with audiophiles???

Thanks for your answer. My general comment about what folks have said so far is that I understand (of course) the concept of what "breaking in" means -- and the phenomenological characteristics associated with shoes, shirts, even the way a lawn mower starts right up (or a key fits a lock) are all familiar. What is helpful in these posts (and in the many other posts which I will go check out), is when some specifics about what-one-would-experience with a broken-in-preamp vs. a broken-in-amp vs. a broken-in-speaker, etc.

Your answer, Millercarbon, makes sense to me -- "All start out with whatever fundamental character they have, but thin and etched or grainy, and then over time fill in and round out becoming more palpably real." That is a recipe for simply looking for what's dominant in the character of the thing and then watching as it deepens/enhances. Beyond that, what I wonder about is whether or not, for example, one can count on certain *missing* or *faint* characteristics (e.g. "lack of defined midrange detail in a speaker") to emerge or grow after "break in." That such a think could happen (and when, where, how) could conceivably help someone decide to wait on a speaker, amp, etc. before trading it in, prematurely. 

@ebm...………………………………………...

"This question has been asked and answered 71 times already."

Hmm, I counted 78 times.

LOL! Here we go.