The more I listen to the HP50 the better the sound. It seems that many times when I first start listening the sound is a bit boxy, but it quickly fades away as the music plays. They seem to be some of the easier to drive cans I've tried.
I wear glasses and yes the fit is that of a snug on ear for me as well. I guess I've come to accept this as it doesn't seem to interfere with my enjoyment.
+1. The sound of them grows on you, and is awesome for a closed back headphone.
I actually preferred these to the Oppo PM-3.
While the PM-3's are more comfortable to wear, and are somewhat faster and more detailed in the mids and lower treble, I actually prefer the overall sound balance, bass through treble, of the NAD Viso HP50.
The NAD is more overall balanced to my ears.
The PM-3's sound even more subdued and rolled off in the top octave than the NAD to my ears, and the Oppo's really have no advantages in the bass to me either.
I know this goes against what most others say about the PM-3's, but I did extensively compare them, and my ears preferred the NAD's.
I agree that if Paul Barton ever designs a PSB or NAD audiophile grade WIRED headphone, he needs to try to keep most of the current 'Room Feel' tonal balance, while boosting the top end 2 or 3 db, and the sub bass as well, imho, while greatly emphasizing excellent measurements like the NAD Viso HP50 has, such as relatively smooth frequency response, impulse response, square wave responses, low distortion, etc.
And, I also think I do actually prefer the 'Room Feel' / Harman type frequency response curve over the much more common 'diffuse field' curve.
Finally, I also agree that comfort is one of the weaknesses of the HP50.
If Barton ever designs another top of the line headphone, or headphones, he needs to take this into account, and take a look at headphones such as Focal Utopia, Sony MDR- Z1R, Beyerdynamic T-1, Sennheiser HD800, etc., for ideas on earpad/headband comfort and design.