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

This horse has been flogged to death many times but I'm still going to put in my $.02.

The only relevant point is that you shouldn't make a judgement on sound quality when you first hook up a new piece of gear whether it's a piece of electronics or speakers. If it's the gear changing sound or your brain adjusting to the sound of the new gear - it doesn't matter. Just hook up the damn thing and run it for a few weeks before making a final judgement.

I'm a pretty strong skeptic about things like break-in but I have absolutely heard the effect myself. I'm perfectly willing to admit that my brain is actually what "broke-in" but whatever. Something happened to change what I heard (or think I heard) - that's all I know.

I am always wondering if anyone ever made the following test: take two identical units of cable, subject one to the alleged burn-in, then do blind testing on both attempting to tell the difference.

As if the blind don't have enough problems without you pestering them to listen to your alleged cables.

Speaker break in I think is most important, them amplifier and preamp warm up.

 My speakers took about 100 hours to open up.

now a days, I tested it big time.

 If I cold start my system, and play some music, it sounds “sucked in” or just odd.

when I want to listen, I will turn on my system the,night before and leave in the on position, and that night, usually weekends, the sound is more relaxed, airy, comfortable to the ears.
 
Its part of having better gear, and letting the capacitors and the internals get to a constant temp.
 It is true, I can tell a fairly big difference from a cold play (turn on and play a cd straight away)........VS- my 24 hour “ON” warm up.
thre definitely IS a pretty big difference.

even my wife commented, said it sounded more stadium like and th3 vocals were just more open sounding.

when I listen to my stereo, I will turn on the night before and leave on til the following night, there is a difference.

if it is NEW gear, it may take a couple months for u to hear the difference.

 I’m not a believer of power cables, or (depends on cables) the benefit of rca cables, only u can make the decision.
i did hear a difference between some cheap rca cables vs some audioquest rcas’ a while back.

 When I went to the Groneberg rcas’ I did hear more bass extension, and crisper highs, and a,slightly smoother midrange.
 No joke, I was on the side of snake oil for a long time, til those Groneberg rcas’ we’re hooked up and broken in.

some is snake oil, some is truth, you decide.

When my Energy RC-70s’ wee first played, they sounded cold, no bass, midrange was ........I don’t know, justmnot right, I listen to a lot of metal and blues, and it took a while, as recommended by Energy, about 100 hours for them to open up, and I can tell you what a huge difference the breaking in made.
 The treble, bass, midrange, everything just became more clear, more bass, and the treble really became to my liking, as the Energy’s are an extreme warm speaker (depending on the disc, or recording)
 The midrange is some of the most warmest, and clearest I’ve ever heard in a speaker.

 Not talking about etreme volume, or blaring them, they said louder will result in faster break in, to move the woofers more, etc etc....
.
i just played them moderately until , I could hear an audible difference at mnay intervals ,
so ed has, it was glorious, so Ed has they just sounded like crapper.

 It was fun to hear the many different variations in sound, until they became my most perfect sounding speaker!

im so happy with these,!

now, I have a brand new pair of Odyssey kismet+ monos.
still waiting to be picked up, I’ll be going through another 6-10 months of break in with these amazing Odyssey amps.

 I love hearing electronics change, and become what they are eventually!
 This is why we do it, isn’t it?

enjoy the ride.