[iancraig10]

I go between the hd600 and 650 all the time. Depends what I'm listening to but I do believe that my 650's in particular have changed with time.

When I first had them, I wasn't that keen if I'm honest. Bloated and fat sounding so I tended to use the 600's more.

However, nowadays, I use the 650 more and although they have retained the lower end 'thud', it is actually a clean 'thud' with no overhang. I think that this has happened with time.

The other thing that I noticed is that the pads on my 600's are more worn down than the 650's and that would probably affect the sound.

I wonder whether your 650 pads put the drivers closer to your ears than the other pair that you tried? My 650 drivers are quite a bit further away from my ears than than my 600's, so they are maybe closer in sound. (Although the 600's do sound lighter in the bass region)

Ian