Best CD or MP4 player

It was something wrong with my new headphones. Whenever I play something on
my PC and plug my headphones, it sounds so clear and bass is clean. But when I
put it on iPod or CD player it sounds distorted and bass is shaky. I want something
that can play 320kbps or a lossless like sound. I heard Sony's ATRAC lossless sound
is something to look at. How do you convert something from .mp4 to ATRAC file?

I'm wondering if it could be the headphones or software you are using to rip and burn, I'm not a big mp3 fan but you shouldn't get the type of sound you described. Mine have always been clear just compressed and frequency response not the same as original. Do you know what the impedance of your headphones are you used with mp3 player?