Ben Sollee is not your typical pop singer. Aside from his genre-blurring songwriting — a folk-centric blend of Appalachian roots, soulful vocals and pop-friendly melodies — it’s not often you see a classically-trained cellist tapping and scraping his instrument to mimic hip-hop beats, plucking its strings like a guitar or covering Tom Waits tunes. Not to mention hauling the enormous instrument from show to show on a bicycle.