Beats are caused by the interference of two waves at the same point in space . This plot of the variation of resultant amplitude with time shows the periodic increase and decrease for two sine waves.
Read moreWhat happens when beat frequency is 0?
When it is zero, they are out of phase and interfere destructively . Beats occur also in more complex sounds, or in sounds of different volumes, though calculating them mathematically is not so easy. or else the brain perceives them as two different frequencies.
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