The process of alternate rising and falling the intensity of sound in the resultant wave formed due to the superposition of two sounds waves of slightly different frequency (less than 10 Hz) is called a beat. Each 'rise and fall' in the intensity of a sound is called a beat. The time difference between the rise and fall is called a beat period, while the number of beats per second is called the beat frequency. The beat frequency is given by \(f_b=\left|f_1-f_2\right|\) which is less than 10 Hz.