These headphones are amazing !!! I first got a pair of Grado RS1i's i was hooked at how amazing they sounded . listening to them on my ipod 5th gen (30g) & varoius portable amps (cmoy from ampedup 18v ra1 clone ,Fiio E07K amp , little bear b-1 portable mini tube)  .Wow , I must say the quality of sound was apparent right from the beginning . My first set of headphones Sennhieser HD 558 open back sounded great but still lacked something . the RS1i were amazing the exact sound i was looking for similar to listening to my home stereo (full sound ) ...