At the ripe age of 28, Jon Zimmer is sort of an old fogey. That is, he is obsessive about the sound quality of his music. ... But iPods and compressed computer files ... are “sucking the life out of music,” he says. The last decade has brought an explosion in dazzling technological advances ... that have transformed the fan’s experience. There are improvements in the quality of media everywhere — except in music. In many ways, the quality of what people hear — how well the playback reflects the original sound— has taken a step back. ... In one...