The 4th Voice Creates a 5th Harmony

This here is an amazing example of what makes a barbershop quartet so pleasant to hear.

This song is done a capella, with Hollens playing all the parts. Listen to the magic that happens when three singers become 4. When the 4th voice enters the song, a new 5th harmony is created by a sympathetic chord of all the other voices. This only occurs when adding the 4th voice, and it’s fantastic!

It also does not hurt that “The Parting Glass” is one of my favorite Irish songs: