let me start off by saying i am in the process of converting my Mp3 library with EAC and Lame so the ripping part is all taken care of. ok i have 2 brothers and 1 uses a ipod and the other uses a zune and i have a cousin that has a sansa. my question is this, do different devices have different output quality from the same audio file, meaning if i take a Cd and rip it to my computer and put that file on my zune or ipod will there be a difference in the output using the same speakers

if there is a difference, is there some place where i can look up and see different devices and compare their output?

Come on someone throw me a bone here or at least point me in the right direction cause i can't find any information on this

Try 'Consumer's Reports' or some other product rating service. My bet is they won't have identical outputs, but can you tell the difference? IDK. Why don't you get all three together and see?

Yep...teacher says...do the homework!

While I'm not personally opposed to the iPod and its evil ways of controlling your life and taking your soul to HQ when you've finished with it, here's an interesting, up-to-date and informative place to start:
http://anythingbutipod.com/

Sound quality...read this http://reviews.cnet.com/4520-11297_7-6510133-1.html

depends on the DAC within the device. I can't imagine all three have the same one. You could capture this through your mic in on all 3 devices and compare - if you are truly hardcore.

Generally, quality depends on how much you compress the file. Try to use lossless for each format.