Run-out. Try it yourself

[Владимир Никонов 2]

Listen to a tape of sacred music — Tibetan monks or Gregorian chant. If you listen closely, you can hear the voices merged, forming a single pulsing tone.

This is one of the most interesting effects, characteristic of some musical instruments and the chorus of people singing about in the same key — education beats . When voices or instruments converge in unison, the beating slows, and when the odds — accelerating.

- www.yugzone.ru/articles/zvuk-2.htm

[Владимир Никонов 2]

And now as you can hear and feel the beats at home: you need a partner. Sit next to each other and start to publish the same monotonous sound ("muuuu", "AAAA"... ).

Need to accommodate each other and then you hear the unusual sound it would be beats.

[Ростислав]

Cool!