I do a lot of music listening at home and had originally (unknowingly) ripped all my CD's in 128 aac like Apple told me to. Learning later what the different bitrates actually meant let me to panic that I was listening to "crap". Since then I've started re-ripping my albums (at different bitrates depending on how much I like them). I've also been using WinABX to try and find my hearing tolerance. The results kind of shocked me. I can't tell a difference between 128 mp3 and WAV, much less 256 aac and WAV. I've tried 320, v0, alac, flac, etc. and I really end up guessing everytime. I cannot hear a difference at all. So, long story short...am I just deaf or am I doing something wrong? I use dbPoweramp to rip from the real (not burned) CD's everytime. I listen through my headphones that aren't terrific, but are certainly better than the stock iPod headphones. They are Sennheiser HD515's. I'm just using my integrated soundcard on my computer (not sure what it is other than a Realtek built into a Abit motherboard from about 2 years ago). The songs I've been using are from Pink Floyd - Darkside, Brian Eno - 2001, Jay-Z - the black album, Avenged Sevenfold - City of Evil, etc. Any thoughts?