Many years ago, waiting for a good friend outside of a Starbucks one evening,he came along at the tail end of one of these and, even though he was/is a concert pianist he could not place the music and lo, these many years later he did place it.
Really enjoyed. It reminds me of the time when our university and a renowned flamenco guitar is, and play. He played completely acoustical without a microphone and was heard throughout the whole theater. That too, was a magical experience I'll never forget.
hug
Kathy
Ron