Thanks for the feedback. Not sure I'm on board with the benefits of using a USB flash drive over an iPOD. Just ripped the same track in every option my MAC's itunes offers and did a test to see what plays and what doesn't.
Apple lossless does not work.
AIFF does not work.
AAC works at both 256k and 192k. (somebody mentioned AAC lossless, not sure what that means because to my understanding AAC is a lossy format)
MP3 works but who cares?
For my ear music encoded in Apple lossless played via an iPOD gave better quality sound than AAC at 256k via a USB flash drive. I realize that using an ipod adds in a D to A and then A to D conversion but the lossless file has much more info. In general the larger the file size the better the sound quality you can expect. The AAC file is 7.3 MB while the Apple lossless file is 27.9 MB. Likely the AAC file would sound better on the flash drive over an iPOD but that seems a moot point when a iPOD can play lossless files.
If I'm missing something PLEASE let me know. I want the best sound quality out of my "Enhanced Premium Sound" package, which to my ear sounds pretty good. I appreciate well recorded music and enjoy it even more when it is played on a quality system. (I just ordered the Akrapovic evolution exhaust so I might not be able to hear the sound system anyway
If anybody knows a way to play AIFF (39.2 MB for the track referenced above) or any lossless file on a USB flash drive I'm all ears. Lets put all of our minds together and figure out the best possible sound quality we can input through that USB port in the center console.
PS I used the EQ settings posted by Pencil Geek and found they made a nice improvement in sound. My thanks to him for taking the time to contribute something so valuable.