ok...this weekend I had time to really sit down and listen to the X. I used both the included iems as well as ones that I have. The iems and headphones I have are not considered audiophile quality but I think they sound pretty good. I did not hear any hiss with the included ones or the ones that I usually use. I then listened to a full cd of The Who Who's Next and thought I detected slight hiss with the included iems. So if the hiss is there it's every so slight for me. Also, I never hear it when the music is playing. The device sounds great. Hope this helps. I saw the other thread about hiss and it seems to be a real issue. I do think it's there but it's not enough to for me to really notice without trying to. I'll have to try some really high end cans sometime and see if that makes a difference.