Here is my recent attempt. This expresses my personal opinion:
A ton has been written, but here are some comparisons:
- The HD650 is smoother, the HD600 more analytical.
- The HD650 sound stage is better, though only by a smidgeon. Its more 3d though the HD600 is no slouch.
- The HD650 is more bass heavy and warm, the HD600 more treble heavy and bright.
- Both of them have stellar mids.
- I think when all said is done, the HD650 is more overall balanced. If they were priced the same, I would prefer it. With a price difference of $100, its really close. I think the HD650 is probably the better long term bet.
- The people who most disagree with the above sentiment are classical nuts. The HD600 does all kinds of music really well but especially excels at classical. I'd pick the HD650 for every other genre, except maybe metal, etc. The HD600 is faster than the HD650, I think.
- Both are very recording dependent, in a good way. Today, get this: I was listening to a recent recordign from a Sansa Clip+ flac straight to my HD600 (my ipod finally croaked) and I was still blown away at how revealing the HD600 was. I heard details I never heard before. This was unamped and an album I've listened to a ton of times. I think the HD600 is more revealing than the HD650.
- If someone were giving me a gift, I'd pick the HD650. Spending my own hard earned money is tougher...
- Honestly, though, I've ab'ed them both back to back and its more like comparing kinds of different central american coffee than it is comparing indonesian and central american coffees (if you drink coffee). Sometimes you can't really tell them apart...