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

Some caps need as little as 50 hours. It depends on the construction design and physical size.  For example,  Jantzen Superior Z caps need only 50 hours, however Duelund copper foil (PIO) caps need all of 500 hours.  Just the way it is.  

shadorne..Disagree with your assessment on burn-in. In the Spring of 1994 I purchased a used pair of Camber 3.5ti's from a member of the Washington Audio Society. At the time I had a Carver system and one of the two very best CD player's from Denon. Several day's after purchasing, I settled down for a long listening session, and was ticked off since one of the woofer's had severe break up and distortion at low frequencies. The titanium tweeter and woofer were from SEAS. I called the seller and he admitted the first day he had them, he drove them very hard with a low powered tube amp and a high powered solid state amp.
I took the speaker's to a speaker repair service company in Bellevue and was told the piston was damaged and the woofer had to be replaced. The cost of the woofer and repair came to $115.00 and the seller refunded the cost for repair. For those who plan to put speaker's in storage for an extended time, store the speaker's face down. Since the piston is suspended hanging off the back of the cone, the piston will sag if inactive for several years and storing them face down will keep the alignment perfect.

@audiozen 

No worries. The videos I linked to are about ATC testing process. I know ATC are delighted that most manufacturers use mass produced OEM Seas drivers. ATC would not have an enjoyable niche producing higher quality parts in house for higher quality speakers if every speaker manufacturer built to such high standards. It is a good thing that other manufactures believe in using cheaper parts and telling their customers to expect significant audible break-in. In a way, you are supporting a tiered speaker market which keeps everyone happy.

Shadorne-Your not making any sense whatsoever. You need to do more homework.
A piston is a piston, doesn't matter what brand it is if its deemed high end. And unless its burned in at the factory before boxing, which most speaker companies do not have the time for, it will always need to be burned in to loosen up the throw motion of the piston.

@audiozen 

This is a speaker forum not a car forum. There are actually no pistons in a speaker. I hope this makes sense.