If you are planning to buy them to use with a portable player unamped, then you'll will probably be better off saving some money and getting a cheaper dual-driver armature IEM like Westone UM2 or Jays Q-Jays, or a high quality dynamic IEM, like Denon AH-C700 or FutureSonics Atrio M5. Shure E500 will work OK unamped out of an iPod, but most likely nowhere near their full potential, unless you got an iMod or some vintage Sony PCDP with an amped line-out. More precisely, out of low-quality sources, the Shures may sound a little thin, muddy in the bass and lacking in the treble and so not very pleasant to listen to. Just my 2 cents.