Very good question.

This is an idea I've thought about, for a while. I'd definitely use an app or tool that would help people learn sing together, in harmony. Making it myself - that's another story.

Here's what I envision. People would be together in person, and the help would be be in the form of earbud - just one - for each person - connected with an app on someone's phone. The app would be coordinating the song.

There would be multiple singing parts. Then for each part, the earbud would feed you the notes (and maybe lyrics), in triple speed, just before it was time to sing them.

I think something like this would make learning to sing in harmony much easier. And it wouldn't require highly trained choirs or choir directors, or a lot of time.

And singing in harmony with other people is such a beautiful, life-affirming activity.