Sounds that are not

Let’s listen to a tape of spiritual music — Tibetan monks or Gregorian singing. If you listen, you can hear the voices merge, forming one pulsating tone.

This is one of the most interesting effects peculiar to some musical instruments and chorus of people singing in about one key — the formation of beats . When voices or instruments converge in unison, the beats slow, and when they diverge — they accelerate. Continue reading →