Though I’d considered it to be the exclusive province of college students lurking under stone archways, it seems that a cappella singing is engaging the talents of a much broader range of performers these days.

Pentatonix, the Texas based quintet leading the art form’s revival, has delivered a string of hits and interesting performances since winning “The Sing-Off” on NBC in 2011. Their recent Christmas album topped the Billboard charts, and this performance with Dolly Parton of her 1973 hit is up for Best Country Duo/Group Performance at this year’s Grammy’s.

In 2013, around the same time the movie “Inside Llewyn Davis” went into wide release, an all star cast put on a concert to celebrate the film’s music. One of the songs from the movie performed at the concert was “The Auld Triangle”. The performance includes most of those on the movie soundtrack, including Chris Thile, other members of his Punch Brothers outfit, and Marcus Mumford – minus Justin Timberlake.

Professional musicians are contributing only a small fraction, it seems, of a cappella performances – as a cursory trip around YouTube suggests.  Indy Dang, an film student at the Rhode Island School of Design, has a YouTube channel with 15,000 subscribers checking out his expanding set of arrangements.   He’s not the only one making these covers of pop songs, but it’s hard to find anyone better.  Here’s his version of “Heathens” by Twenty One Pilots, a song from the soundtrack of the summer hit movie “Suicide Squad”.

No talk of a cappella singing is complete without mentioning The Persuasions. The group made it big after Frank Zappa heard them perform and booked them to open for the Mothers of Invention at Carnegie Hall in 1971. Here is their excellent version of “People Get Ready” written by Curtis Mayfield.