The iPod revolution has changed the music industry, but five years after the personal jukebox was debuted, no one has yet figured out how to bring high-quality sound to the portable players. “Listeners demand portability and a la carte song purchases. But at least some also want ‘fidelity,’ to experience a sound that’s true to the full aural expression the artist poured out at the moment of a work’s creation. Technology, artist advocacy, and buyer behavior will determine the degree to which listeners can have both, experts say.”