Finale watchers alerted me to this video interview with Deke Sharon, the “musical force behind NBC’s ‘The Sing Off’ and both ‘Pitch Perfect’ films.” Among the highlights is a cleverly-edited sequence where he sings each part of an a cappella arrangement (seen in Finale 2014), and both the audio and the video have been multi-tracked.
Stick around for the end where Deke’s answer to a question – about how the a cappella landscape has changed in recent years – turns into an well-spoken plea that we all get off the sofa and sing with each other.