[pdrm360]

In overall I preferred the HD600 over HD650 until I've heard some music from a HD650 was driven by a Schiit Valhalla, which was fantastic. The Valhalla brings the HD650 to life.

 

[maarek99]

650. To me but everyone hears differently.

 

[cyclingbobe]

I have rediscovered the HD650 which I had set aside for some years whilst I played with HD800; Beyerdynamic T1; Denon 7000 , Ultrasone Edition 8 and a number of cheaper phones which I could use direct from my iPhone including Sennheiser Momentum; Beyer T50P; V Moda 100; and various IEMs. At the end of all this I am amazed at how good the HD650 s are. Using them with a Lehmann Black Cube amplifier with a feed from a Fidelity Audio Dac with best quality files from an iPod, they make everything sound realistic but without any tiring harshness or veiling. In comparison the 800 can be too brightly lit; the Denon too tubby; and the Ultrasone detailed but wearing and compressed. The only ones that compared were Phillips Fidelio X1s: a real bargain may I add. 
Of course this is through my ears and we all know about physiological and psychological differences but my advice to anyone seeking a top quality headphone for use with a home amplifier or a good portable  amp look no further than the HD650. It has stood the test of time and is still used in many studios. I noticed in a recent video of Lang Lang recording with Simon Rattle all the mixing engineers were wearing them. 
I have enjoyed the HD650s so much I have ordered a pair of HD600s which some still prefer. 
Interestingly a colleague who recently asked Sennheiser what he should buy to equip a new recording  facility was advised HD650s!
Do give them a go!
 
Roger

 

[iSennheiser]

As a musician I prefer HD600, the only headphone that I think is the most truthful to the original recording, closest to the real you can get( for the price) , HD650.. Probably for those of you who love colored music such as electronic dubstep and modern punk. If you've been to many concerts and classical concert hall, HD600 is the way to go or step up to HD800 or audeze lcd2, peace.