Singer, songwriter, producer, and all-round entrepreneur Peter Hollens is a champion of a cappella singing dating back to his days at the University of Oregon, where he founded the college a cappella group On the Rocks in 1999 with Leo da Silva. Hailing from Ashland, Oregon, Hollens earned a degree in vocal performance from the University of Oregon, where he became active on the college a cappella circuit, producing, recording, and judging competitions. He started his own YouTube channel in 2011,...