headphone requires about 100+ hours to burn in properly.

AT LEAST 200 hours burn in time before they sound their best

which means solid 10-12 hours of music and you still wouldn't have a fatigue due to these headphones or their clamping force

John Grado of Grado headphones says 50 hours is a good burn in time.

I did put about 40 hours of playing Golden Earring CD to break in the 990 Pro's before evaluating

Others say the AKG 701/702 require about 300 hours to burn in properly.

That said, less than one hour of listening is hardly enough to judge long term comfort.

The reason I'm writing this review is that I assume there are people like me out there who prefer their sound to be in a more powerful U shaped equalization curve.

but when you do these things will shine and are without a doubt the best U curved headphones I've owned.

Has a Lovely and vicious U curve