OK thx I will look for some other cans, but please report if the beyer pads will improve the isolation, on my list is ATM Shure 840 and Kenwood K1000 I don't think I will buy the K271 as I allready have the K400s and I suspect they have a similar soundsignature.
The Kenwood K1000 would be a fine choice, but are IMO not that much better than the K271 when it comes to sound quality. The K1000 have way more bass though. K271 isolates better.
The K271 and the K400 have not the same soundsignature, especially not the early production K400. Those are far more lively, with a much better overall sound and soundstage than the K271 have.
The Kenwood and the K271 share more similarities in sound than the K271 and the K400.