Just out of curiosity, what do you think are the differences in sound between the K271 and the K272?
At least to me, the K271's offer two variables that allow them to sound a bit different than the K272's. The first being that if you keep the stock leatherette pads on, instead of switching them out with the included soft velour pads (which are similar to what the K272 has), the seal over your ears is a little tighter, which blocks out more outside noise, and seems to add to the bass, but also takes away from the comfort level a bit. The second being that you can replace the stock XLR cable; I use an
Oyaide HPC-X35 XLR, which seems to add a bit of clarity and richness to the sound, especially the highs. Overall, with different pads and a different cable, the K271's end up sounding a lot less "laid-back" than the K272's, to use a term I've heard others use when describing the AKG sound. I actually got the K271's mostly for use in public; the tighter seal of the leatherette pads, the option of a shorter, more manageable cable, and a "kill-switch" mechanism in the headband that mutes the headphones when you remove them from your head make them more suitable than the K272's for a portable rig (about as portable as any AKG K-series pair of headphones can be). The difference in sound was honestly just a "happy accident".
I know this may sound a bit odd, since I'm not particularly well-versed in audiophile jargon, but I would best describe the difference between the two like this. If you were at a bar listening to a jazz band, the K271's would be the seats directly in front of the band, maybe one or two tables back; the people sitting there might enjoy a drink or two, but they'd mostly be focused on listening intently to the music. The K272's, on the other hand, would be the seats farther back towards the bar, including the bar stools; the people sitting there would be there because they appreciate the music, but they might also be reading, doing work, etc., and while the music still sounds beautiful, it might serve a more ambient role.
Having said all this, I honestly couldn't see myself owning both of them if they had price tags similar to the K701's, but since the K272's and the K271's with a decent aftermarket XLR cable can both be purchased for about $150 apiece, they're different enough in terms of sound and also ergonomics to justify owning both of them.