Summary: I like the HD650, in fact I like it alot. My primary issue with it, is the fact that it exhibits its sonic signature at all times. I have heard the HD650 on a large variety of amplifiers, and configurations. The HD650 seems "disconnected" when trying to convey the immediacy of rock or alternative music. This is not very noticible until one utilizes a headphone that is better able to "chameleon" itself. That's not to say the HD650 is not relatively satisfying in itself.
Pros: I am chuckling as I read the other reviews. I have been an audio junkie for 40 years. I have never heard anything as good as these anywhere near the price range. You can wear these for hours in comfort, too.
Cons: Not really designed for computer junkies. These full range headphones demand more power than most computers put out.
Summary: Jus got the hd650's about 2 weeks ago...I've broken them in, and let me tell you, they are the closest thing to being at the recording studio with the band!! I mean, they sound so real, and authentic, that its unbelievable!! i mean, what can I say? They are one of the best headphones out there, and I would truly recommend them! The sound is very natural, and laid back. Want the best? Look no further! They're right here! Sennheiser hd650...the best...
Summary: Very good base that does not distort the upper frequencies. Only minimal distortion in a few songs is noticeable. Go to headroom and look at the frequency response chart and you'll see why. Some of the high frequencies DB are dramatically lower, so if something in the music is that frequency it will be drowned out. The headphones clamp very tightly so they're not as comfortable as I would like for [$].
Summary: This is the best headphones that I ever had. After spending couple months of reading and researching in forums, I decided that spending a little more on this decent headphones is a long-term investment. The old saying is right - you get what you pay for. And I'm happy that I didn't go cheap and pick the lower-end ones. This one really brought me back to the world of music and there's no word to describe my excitement when I put these on the first time.
Pros: Comfortable, Durable, Good Bass, Good Value, Great Sound, Lightweight
Cons: Open back design. If you are listening/working in a loud environment, you will have to depend on louder volumes to attain consistent non-interupted listening (vs. closed back). Can also be more of a problem (vs. closed back) if liquids are involved.
Summary: HD 650s are my favorite headphones and they are quite easy to be drive by most headphone amp after a well burn in. With the Cablepro or moonaudio upgrade cable the sound of the HD 650 are very well described. Bass are controlled and impactful, I use the 650 for most rock, jazz and soundtrack since most of the are bassy music. the 650's detail is not as good as K701's and RS1's but it gives you a big picture of the music you listen.