National Public Radio's show Alt.Latino just aired a segment in which they discuss the theremin with members of the band Los Macuanos. You can listen to the full show here. The interview with Los Macuanos and discussion of the theremin begins at around the 17 minute mark. They credit May Roosevelt with the theremin performance. They don't quite get the story of the discovery of the theremin right, but we'll let that one slide.
Check out Los Macuanos' latest album El Origen
