Pros: open sound, sufficient bass, mids are awesome, no sibilence
Cons: not for treble fans
These cans offer great multilayer-ed sound especially in comparison to entry level headphones. As I am upgrading my gear in a linear fashion, my last cans are HD448 just a step below these.I believe you already have a decent idea of how these cans sound if you frequent here often, for variety sake, I will try to base review in context to my prior experience ie what such an upgrade brings to the table.
When I put these for first time, I was disappointed. After plugging in amp, they sounded as muddy as my $10 earbuds. I had heard these cans needed short break in which was absolutely spot on. In less than 10 hrs, sound started taking its place.
These cans are clear upgrade over hd448. Sound is 3 dimensional, multilayered, which I believe brings biggest improvement. It enables much better instrument separation, does justice to each one of them and bring in a lot more detail. A higher end can like HD650 may do a better job at doing this, but thats why you pay more for those. HD650 are described by many as dark cans having great bass, smooth mids and good sound stage when used with right amp.
I will use similar adjectives to describe these except these are much more lenient in amp requirement. Sound stage and open sound is a given no matter the source. Though a portable amp must be used. Bass is punchy and mids are well rounded. So I find these to be great all rounders suitable with all genres I tried. Sibilance is not a problem as these are dark sounding cans.
I think I like this sound signature so upgrade path is clearly paved unless I venture around for variety sake.
All in all I did'nt gave it a 5 star cause I don't wanna come back and reduce rating after hearing a much better can.
Edit: Some observations after extended listening:
Moderately diffused presentation: Instruments sound like in a mid sized room and a bit distant. They don't sound close or in your face at all.
Slow and laid back: Really good if you listen to them to relax.
Smooth, not utterly detailed: Micro details are a bit of mixed bad. Some time they come out note to note, sometime it doesn't. Overall smooth sounding.
Tend to hide some instruments when a lot is going on.
Black backgrounds on my amp. Good contrast between instruments.
Thick sounding and rather natural mid range. Bass is extended but texture varies from song to song.
So not an end game headphone but extremely enjoyable. You will love what you hear if you are just enjoying music instead of looking for technicalities.