NEWSDAY: How Pentatonix, ‘Pitch Perfect’ have made a cappella mainstream
How Pentatonix, ‘Pitch Perfect’ have made a cappella mainstream Updated February 13, 2015 2:53 PM By GLENN GAMBOA glenn.gamboa@newsday.com (L-R) Singers Mitch Grassi, Scott Hoying, Avi Kaplan, Kirstie Maldonado, and Kevin Olusola of Pentatonix, winners…