I think the K-1000 is one of the ugliest, doofiest looking, cans ever put out there (with the exception of that Magneto helmet I sometimes see with the goofy guy smiling underneath). I've never actually heard them, so I'm no judge of the sound. I'll put that up front. But what the K-1000 appears to do is give you the driver and practically nothing else. There it is in all its glory. You can adjust the big waffle pads so that you can play with the axis and orientation but for the life of me, I don't see why that headphone needed such an overwhelming headset for something so basic. I also don't see why a pair of mylar drivers merited a cool grand. Is this the audio-fetish concept car or what?
What I noticed, when I bought a pair of K-701s, was the degree to which the back vent had obstructions preventing it from being a strictly open can. Doing so would not have improved the quality of the HF. I can only surmise that it was done to give these headphones more kick. I'm not sure the K-701s are really an example of great kick, though I thought the crystal-clear highs were a lot of fun. I'm inclined to think that the future of high-end headphones will involve more semi-open cans, with designers building enough of a shell to capture enough bass while leaving enough of an opening to vent unwanted HF. Sennheiser seems to go for the intermediate filtering, where there's some veil between the ear and the driver. I don't much like that. It doesn't feel as dynamic as my Grados, which leave nothing between ear and driver. I'm more in favor of damping all around, both around the driver as well as behind it.