I just went to the B&O store to test the H6 v1 and v2 side by side. I was in a very quiet environment, and I tested both headphones directly through my phone (keep in mind all my music is in FLAC). Also, feel free to go on youtube to listen to the music that I mention if you want to get a better understanding. Keep in mind that I only spent about 1 hour and 20 mins comparing the two.
Build - Pretty much the same. Nothing to remark here. One thing to keep in mind is that the "natural" color variant of the H6 (white and beige) is lighter on the v2.
Comfort - The v2 has a slightly looser clamp than the v1, which may help with comfort. If you find the clamp to be too loose for you however, you can always bend the headband to adjust it.
Sound - Now here's the important bit: the sound is different, no matter what B&O tells you.
Bass - There is more bass on the v2 than the v1, no question about that. On "Take my Breath Away" by Gui Boratto, the kick drums had noticeably more impact than the v1, yet still felt controlled, and I could still make out the sound of the actual kick drum. For house and party music, that's a good thing. Next, I tested with "Back in the day by Erykyah Badu. Usually, if a headphone has too much bass, the low-mid keys in this song will be drowned out. I'm happy to say that it was not the case for the v2, and the bass was right where it needed to be. Finally, I played "Take it There" by Massive Attack. The bass boost gave the kick drums impact, yet it blended in when I didn't focus on it. To sum up, you're definitely going to notice that these headphones are not neutral, yet the bass boost does not stick out, and certainly does not drown anything out. My only gripe was that it could have been a little tighter/faster, though it was definitely not muddy or boomy.
Midrange - I tested the midrange with "Unfinished Sympathy" by Massive Attack, "Morning Child" by 4Hero, and "'Tis a Pity she was a Whore" by David Bowie. I could hear all violins and brass instruments perfectly fine, no problem here. Vocals were slightly recessed, though I had to comprate the two headphones to make it out. To be honest, I really don' think there is any noticeable difference here. Next.
Treble - It's the same. Perhaps if you somehow magically made the v2's instantaneously turn into the v1's on my head, I would be able to tell a slight difference, but after taking the headphones off and putting the other ones on, I couldn't tell any difference.
Soundstage is the same.
Summary:
The biggest difference between the v1 and v2 is dat bass. Now, after having read this forum and what I said, you may have been led to believe that the bass has been boosted to mh40 or HM9 level. THIS IS NOT THE CASE. On those headphones, the bass is noticeably boosted to the point where it sticks out. The bass does not stick out on the H6 v2. Simply put, you just notice that the headphones are not neutral if you are playing a bass heavy song. If you play jazz, bass-light rock, or classic, the difference will most likely be too small to matter. In my opinion, the bass boost is a good thing, since the bass is the first thing to be lost when you step outdoors, which is a big problem with the v1's (EQ's are often a bad solution). Overall, the bass is right where it should be on a portable headphone, and everything else is pretty much the same after 1 hour and 20 minutes of comparison. I will be ordering a pair of v2's as they are more suited for portable use. Sorry for the length of this post, I hope this helps you. (and feel free to contradict me, as 1 hour and 20 minutes may not be enough to properly compare the two, and I may have skipped over something I shouldn't have)
