Ever since the Walkman, ordinary people have had the ability to soundtrack their lives. You can play familiar music to reinforce or change your mood, music that either fits the tone and speed of your situation or is purposefully set against it. Earbud listeners can seek solace in this private musical headspace, an environment of their own making. Now imagine this, what if your personal soundtrack could change dynamically? What if technology existed that took into account weather, time of day, and your exact location and activity? When you breach the threshold of your door, one song crossfades into another.…