My HD630VB came about a week ago and I have been testing ang burning in them since.
My first thought they had piercing peaks mostly above 12khz. Then I realized that was becasue they weren't covering my ears fully because of my glasses. Once those pads break in and isolated my ears with the glasses better those peaks got significantly lower. I was also testing V5i opamps in my amp (which they were a little bright). And they are definetly not good pair with bright opamps earpiercing in the highs. When I went back to my stock opamps they got much better. And doesn't scratch my ears anymore.
Sound signature is just a little close to A5PRO. Those frequency response doesn't really show how the headphones are unless you listen to them. They have much more resulotion, a little more clear, highs extens more, more detail, really good sounstage (it can even compete with some open-back in that area). And the sub bass where this cans shine.
But they have flaws also. Low mids and vocals seems a little laid back compared to A5PRO. Highs are clear and much more detailed but they have some peaks which might be disturbing to some. I'm using the sub bass one level below the max, by using that it is masking those peaks by overhelming in the sub bass area(besides it seems I really like the sub bass power). A5PRO's highs doesn't have any peaks, warmer and darker compared to them.
If A5PRO had the power of the sub bass that HD630VB had I would have chosen A5PRO over it because vocals and mids are really good and open with them and doesn't have that peaks. But still now I tasted the power of the sub bass with exceptionally good clarity with mids and highs I don't wanna use A5PRO anymore. HD630VB are really fun to listen. When I was listening to A5PRO they tended to put me sleep.
The bass dial are really usefull for listening different genres. If you want to hear more detail simple turn the dial down. If you want more energy turn them up. But still these are definitely "NOT BASSHEAD" headphones. My XB950N1 even without the bass effect on shakes your spine. They had much more mid and high bass. What HD630VB has more in the sub bass area. They don't shake your head. They have the power of the sub bass while not getting in the mids and have perfect resulotion and highs.
Only thing I don't like with HD630VB those little high peaks. I believe they will get better with more breaking in with the pads more isolation. Having to wear glasses effects much with these cans. Sounds leaks through there and making peaks worse. But more I use less peaks I get means pads are starting to match my heads. I have never changed any pad with any headphone so far but this might take more benefit with better pads.
When I got A5PRO first it had too much distortion. And after a lot of time usega that did dissapeared. I didn't see this much change by breaking in with other headphones and I thought burning in was much of a snake oil. But once I saw A5PRO change I said burning in real at least for them. Time will tell how the HD630VB go.
Note that I'm using a SMSL VA1 amp and it has low and high gain(impedance) output. I have heard that if you connect a low impedance headphone to a high impedance output you would get lower bass. I haven't noticed that with any other headphones I had but it seems there is significantly difference in the sub bass area with the HD630VB. If someone connect these to a high impedance output they would even think the bass dial doesn't work. They don't have that issue with the low impedance output though.
These became my favourite headphones right now and I'm perfectly happy with the purchase. They get more and more enjoyable with listening to them.
Just wish they had detachable cable though. Sennheiser showed they can be changed with a little surgical operation but those cables aren't in stock even if I willing to do that. That is the biggest draw back with this solid build headphone. (A5PRO's more solid though you can use them as a weapon)
