help which beyerdynamic for me !!

Hi can naybody tell me if the beyerdynamic dt770 are good for use with my iphone 4/fiio e7 amp? also what ohm do i need 16 or 32 ?

 

And are they good honestly good for keeping noise in and out, ie do they leak at high volumes, oh and of course i only be using them for home use, or any other recommendations please..

 

Cheers from Brian

Hi and ye ive just been told they the best of what im looking for, are they good for isolation and do they leak at high volumes? Any other suggestions as ive tried sens hd25 1 11 and they leak terribly, even though they sound awesum, also tried shures srh440 and they do aswell..