Compare to the visual stimuli, the auditory stimuli are usually much more subtle. But there are still beliefs that mp3 128kbps has terrible sound quality compare with 320kbps or raw wav file.Of course, technically (data-wise) it’s different thing.

But do you think it’s true that you can distinguish them? Well, you can try it out here. 

http://www.noiseaddicts.com/2009/03/mp3-sound-quality-test-128-320/

By the way, I could hear out the quality difference with my $15 Koss earphone.