Overtones are nature. ((Summer Cottage)) They were first posited by a pre-Socratic philosopher named Pythagoras, who described them — they’re also described in Helmholtz’s On the Sensations of Tone. ((Exploration In Vibration)) And if you play a low C on a piano, let’s say a C below middle C, I mean you’re going to hear the fundamental. I’m not sure that’s a Do, but you know, whatever.

You hear the fundamental sound, but in addition to that sound, if you listen very, very carefully, you’ll hear other frequencies in the composite waveform. And so, what you’ll hear, if you listen carefully, is a C and octave above the C that you hit on the piano, and then you’ll hear a G above that, which is a perfect fifth, then another C an octave figure, then an E, a major third, then a G of another perfect — that’s a six overtone. The seventh overtone is a B flat, but a minor — so, C-E-G-B flat. Everybody knows that chord. But the B flat in the overtone series is significantly flatter than what we have in equal temperament for various reasons, and it’s very, very, very beautiful.

And then it continues to go up. The 8th overtone is an octave C, 9th overtone a D, 10th a C, and then you get this like F sharp, and it starts to get in A flat, and another B flat, and it gets very, very weird. And they’re soft. And we’re not trained to hearing them. So, when I got into my guitar pieces, particularly with the piece Guitar Trio, which I composed in 76′ and 77′, I wanted to use the entire harmonic and melodic vocabulary, these overtones. And the advantage with the guitar is whereas — when you play them on piano, they’re soft and they’re hard to hear. On guitar, you can pump up the volume. And these overtones, which before in the real world, were so soft and so delicate, in guitar, become like singing choirs of angels. ((Choir, Church Has The Best Tunes))