I have a pair, and I'm listening to them as I type. Ignore pretty much anything I've said about them prior to this. I didn't burn them in prior and was on something fierce. (Do I have to say I'm kidding?)
I personally think they can hold their own, maybe even outperform the K271. During the short time I listened to the V6 and DT770, I preferred the DT220 to them.
I'll describe the sound and some comparisons in a few sentences. The bass is rather tight, deeper than the K271. They have much less bass than the DT770, but more detailed. Too polite for bass heavy electronic tracks.
The mids are forward. Not Grado forward, but more than neutral. Male vocals have a nice amount of body, female voices are not as good as the K271.
The treble is nice, not piercing, not too mellow, not quite sparkley, but getting there. Suitable for jazz and the like. Saxophones sing with these.
Soundstage isn't the biggest in the world imo, but I've been spoiled with ATs. It's smaller than the K271, but a bit more precise. I didn't get the chance to really listen to the soundstage of the DT770 or V6.
Details are very prevalent, well for the price I paid ($30), heck even compared to everything I've heard <$100. Lyrics for pretty much any artist I've listened to are completely clear, save Coheed, which must be intentionally garbled
. In classical, every instrument is easy to discern.
The driver housing presses onto the ear and starts to hurt after a while. If you can, I'd try to make pads, but I've tried to make thicker pads but they always kill the sound. The vinyl pads get really warm after a while too.
This obviously is a cruddy review but I really am not in the mood to be doing anything (sickish, muscles hurt), but I feel I should post something because you inspired/came up with a feasible prototype for me to make a K1000 style 'phone so this is the least I could do.
If you want any more specifics about treble, mids, or bass, lemme know and I can add more. Just wanted to give a basic idea.