auricgoldfinger
500+ Head-Fier
Near the end of my listening session last night, I picked up on a little weirdness in the mid-range -- the "perceived deficiency," as @auricgoldfinger described it in his posts (he uses an equalizer to correct it [1db boost at 1000 kHZ]). It's not a consistent issue -- with some music I noticed it, but with other music I didn't. I heard it most when I listened to songs in which the vocal was buried in the mix. In those songs, the vocal sounded as "laid-back" as the HEKv2 did, but that difference was only noticeable because the SE's sound is more forward and has greater clarity than the HEKv2. When I listened to songs in which the vocal was in front of the mix, the mid-range sounded fine.
Again, these are my impressions on the first day with the headphones straight-out-of-the-box. There are many factors in my audio chain that may have altered the sound, and the weirdness may go away with burn-in.
The midrange will fill out after 150-200 hours.