Speaker Break-In - What Physically Changes During Break-In To Enable Better Sound?

No, break in requires more time for the extra large caps made by companies like Jupiter Condenser and Duelund. Values for passive crossovers from 5-10uf are the size of Coke cans. These windings take 500 hours of run in and experience from pros proves this out.

Caps should be reformed before you receive them if the speaker maker chooses such caps that require it. Otherwise this is not high quality production. High quality designs will also avoid passive crossovers for a multitude of obvious reasons.

Capacitors don’t have windings. You are thinking of transformers.

The choice of “fancy” crossover parts in a speaker with cheap OEM drivers is the oldest marketing game in the book. Of course OEM speaker manufacturers dwell on this because the box and the crossover are often the only things designed by the manufacturer, the rest being assembly of OEM parts. Again design choices can be made to build to tight overall reliable tolerances or driven by marketing claims by installing fancy stuff between ho-hum drivers.

@shadorne 

Where do you get this silliness you speak of? A new pair of jeans needs broken in. New shoes need breaking in. Engines need breaking in. A new bed needs breaking in. New tires need heat cycling. A new bike needs breaking in. Musical instruments need breaking in. But a complex mechanical device like a speaker just pops out of the factory perfect? That's so obviously wrong. 

There seem to be two issues being mentioned.
First is NEW speakers/crossovers/ electronics needing time to settle or work into the better sound. Speakers in particular the cone speaker surround, for Magnepan the mylar needs to stretch a little, and all need capacitors in crossovers to break in.

Second is the apparent getting better after turn on of many components.
I agree with both happening.
Anyway, I leave all my stuff on 24/7 to avoid the warm up hour.
(I am retired and listen all day every day anyway)
The one component I leave turned off  still does take about an hour to sound better. (Preamp I have I use only for LP playback)

@kosst_amojan

Did you watch the videos?

You might learn something if you did.

Not all speakers are just thrown together using OEM parts and go out the door with only a go no go test. Some drivers are rigorously built and stress tested individually (extreme amplitude response as well as thermal) and tested against an “ideal response” reference and tested again together in the final assembly. These speakers are already broken in when you receive them. Drift over the life of these speakers is negligible due to the entirely different design philosophy to other manufacturers. We are talking true reference type speakers (with commensurately costly manufacture process) even if the word “reference” is way over used to market nearly every speaker.

True reference is not a “silly” concept it is however expensive and very few speakers are built to such a high standard and this is why many low quality manufacturers will warn you that their device needs to settle and break in at your home for up to hundreds of hours.