iLounge reader, Marc Heijligers has posted the results of his encoding tests for AAC using iTunes and QuickTime. You’ll also find reviews of several headphones and a comparison of the iPod’s sound quality to other audio digital devices.
iPod sound quality and AAC encoding tests
“Although the AAC 224bit/sec shows some artifact, you have to compare it with the original and critical source material in order to recognize those artifacts. The AAC 320 kbit/sec encoding results in much larger files, for just a little bit more quality, which was my reason not to select it. For less critical material, I use the 192kbit/sec AAC encoding, just to save some space on my iPod.”