Yes, my comments on IE8 burn in can be found
here
Here are some of my burn in points, from memory:
- 20 hours of burn in the soundstage opened up and the bass extended
- 70 hours the treble started to come out
- 100 hours the mid-bass hump was greatly reduced
- 150-170 hours they surpassed the Phonak PFE (w/black filters) in detail. Mid-bass was down even more from 100 hours, and the treble was opening up. The soundstage seemed to widen quite a bit more.
- 200 hours the treble kept opening up and the mid-bass hump was down even more leaving a warm presentation
- 250 hours the treble is fully opened up, audible to 17KHz (my hearing might be limiting that) see
here for more detail.
- 250+ hours, really enjoying them
Burn in time depends upon personal taste and what other headphones you listen/compare to. Some people like it out of the box, some don't. I didn't, but now I am loving it!
I believe it takes somewhere between 200 and 250 hours to fully burn in, YMMV.