IYAshike
100+ Head-Fier
The D600 definitely has a very colored sound for something in its price range. I found it enjoyable at first listen, but the weirdly distant vocals made me return it. The "veiled" HD650 is a lot closer to neutral.
With all my respect, that "distant vocals" you mention is very misleading for people reading this thread and willing to buy the D600. The vocals are only recessed in tracks that are recorded that way. Just to give an example where the vocals are definitely not recessed, at all, you can listen to the famous album "Best of Jazz Audiophiles Voices". Now, if you like 'neutral sound' or (so to say) 'very-forward mids', then these Denons are certainly not for you.
When it comes to me, l keep on enjoying them. l really love the bass they provide and how they excel in movies!