Mastered for iTunes: how audio engineers tweak music for the iPod age
Music throughout the last decade is typically recorded using 24-bit samples at 96kHz, and advances in computing power and hard disk space have recently made even higher quality, 24-bit 192kHz digital recording possible.
However, even the standard CD format comes in a much lower resolution???just 16-bit 44.1kHz. Compared to 24-bit 192kHz digital audio, a finished CD only has roughly 15 percent of the information captured during the recording process. Compressing the songs on a CD further into 256kbps AAC “iTunes Plus” format cuts the data down to just one-fifth of the size of CD audio, or as little as three percent of the original 192kHz recordings.
Interesting read for the audiophiles out there.