I just took my DT-770's offshore with me for only the second time, as I wanted to keep them at home as "good" full-size headphones. My Etymotic ER-6i's had been out of commission for awhile until I got a colleague at work to solder on a new minijack. Trouble is, when the jack is turned a certain way, the left channel cuts out. I'm just waiting for these things to finally die, but I don't want to be caught offshore without a proper headphone, and I need isolation from noise.
So, out came the Beyers. My complaints about the Beyers mirror most everyone else's: while the subwoofer level bass is fun and welcome on some tracks, the headphones have a somewhat murky presentation and the midbass can overwhelm details, making them a headphone for only certain songs, and certainly not an all-arounder.
In the area I'm working there is a diesel generator right outside the door, and the ambient noise level even when the door is closed in the office is fairly high. In this environment, I nofticed that my perception of the music from the Beyers is much different than using them in low to no ambient noise environments...that which was bad about the headphones before is becoming good. Because of the incessant drone of the generator the midbass bump is quite welcome, allowing the music to sound full without resorting to higher volumes. And strangely, I can pick out the higher frequencies much better now, making them in general a far better balanced sounding headphone.
I am taking a guess, but is seems that these headphones were probably designed to be used in areas with relatively high ambient noise levels, like as musician monitors in a studio environment where a drumkit, amps, etc. would be blaring, or perhaps for close monitoring of a particular sound source when there were other sounds playing aloud in the background, like in a television studio or control room.
But for their bulk and somewhat high power requirements, they might be excellent street/bus/subway headphones on portable devices. Their non-coiled cable is a good indication that they were not meant to be used in a relatively stationary manner, giving the user relatively wide latitude for movement, unlike the Sony MDR-V6/7506, Sennheiser HD280/380 or Beyerdynamics own DT-250, which all utilize coiled cables meant to allow occasional movement but returning to base most of the time.
I'm glad I discovered this about them, I have always had problems with my Etymotics sliding out of my ears, but I kept hanging on to them because they are so much more compact and sound isolating than anything else out there. However, I think I'll use the DT-770's from now on since I've discovered their usefulness in just the sort of environments to which I'm exposed.