When Sonos was founded in Santa Barbara, Calif., in 2002, the world of the audiophile was very different.

Napster, that early digital death knell of packaged music, had just shut down. The iPod was about a year old and Apple had sold only around 600,000 of the pocket music players. Spotify, Pandora, even iTunes didn't even exist. 

And if you wanted to dig into a deep library of music to play on a high-quality system, you had your work cut out for you. Big-box speakers connected to consoles with a tangle of cables, towers of CDs arranged in meticulous order to find the right album quickly. And if you wanted sound in more than one room, you might need a PhD...