Arriving before daybreak to immerse myself in the Austin phenomenon that is SXSW, I joined a rising tide of die-hard live music fans. A local radio station had set up in an oversized living-room-for-a-lobby at the Four Seasons. Sitting in the round, they live-broadcast their morning show all week—offering the perfect indie-music sampler platter. Two songs per artist, stripped-down sets with minimal DJ introductions—an ideal way to digest the week's overwhelming festivities.

These emerging artists...