CRESCENDOPOWER

These headphones are not nearly as refined, detailed, or have the transparency of many other high-end headphones, but what they do have is the ability to bring enjoyment to the music. Overall, they are a dark sounding headphone, but still have that Beyer treble, that tick, tick, tick on top. First thing that most people notice is the bass, which is almost overpowering, and goes very deep. The mid-bass can be described as anything, but boring; it will knock your socks off with the right recording. As for the soundstage, it is extremely wide, and open for a closed phone of this caliber. But, what impressed me the most about this headphone is the midrange; it is liquid smooth, and sounds great with female vocals.
Like anything in audio, everything that is said is nothing, but opinion, so the equipment best suited for this phone is the equipment that makes it sound best to you. I will comment however, that a more detailed, faster, analytical source is probably a better match. Also, find an amp that has good extension in the treble with a low to medium impedance output.
In ending, I really wish I had had a pair of these phones in college. They have good isolation, are very comfortable, and are killer for hard rock music, which can be played a little louder, because of their dark character. Because of their dynamic nature they definitely get my vote for the best college beer drinking, rock out phones on the planet, with an amp of course.