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Films · Acoustics · Beats

Explainer film · Acoustics

When does one tone become two?

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When does one tone become two?

Whether we hear one tone, a beat, a rough sound or two tones depends on how far apart the frequencies are compared with the width of our auditory filters.

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Chapter 1 · Two tones, one air

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When does one tone become two?

Acoustics · Beats

NewOct 25, 2026 · 4 chapters

An explainer film in four chapters to listen to: two tones superpose. In step makes them twice as loud, opposite phase silent; almost equal tones pulse as a beat, above about 15 Hz the sound turns rough, and beyond the width of the auditory filter you hear two tones. With guitar, accordion, fifth and third. Pause, drag it yourself and ask.

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