Earth Tones

If you know what you do and have the right equipment you can hear our planet emit a soft continuous hum.
After fine-tuning and perfecting your instruments you will notice that if you move around a little on the spot you are listening, the tone or volume of the hum changes slightly.
You'll discover that each tiny little portion of the surface of our planet has its own individual sounding hum, and when heard simultaneously, they produce a friendly low murmur of a hum.
Nice enough in itself.

So one day the Doctor and his good friend The Soul Representative took their equipment up in their balloon, to listen to the Earth Tone from above, record it, and do some thinking.
They brought sandwiches and enough to drink. Each found the other an enjoyable companion on these flights. They would certainly be comfortable for about 24 hours.

After the ascent they "fixed" the balloon so it would remain motionless in the sky, with the earth rotating below at its slow speed of one rotation per 24 hour day.
Then they aimed their directional microphones with pinpoint precision at the precise spot directly under the balloon.
They powered on their recording equipment and switched its output to the speakers inside the balloon's small cabin.

What they heard surprised and exited them in a way they'd never imagined.
The earth rotated slowly below them so they were listening to a sequence of hums, played at the exact right speed.
To their amazement they were listening to Earth Tones music. It was beautiful.

Earth Tones