What phenomenon occurs due to two sound waves of similar amplitudes but slightly different frequencies?

When two sound waves with similar amplitudes but slightly different frequencies interact, they produce a phenomenon known as beats. This occurs because the sound waves periodically reinforce and cancel each other out due to their phase differences, which change over time as the frequencies diverge.

As one wave comes in phase with the other, their amplitudes combine to form a higher sound volume. Conversely, when they are out of phase, their amplitudes partially cancel each other, resulting in a lower sound volume. This cyclical increase and decrease in loudness creates a new auditory effect that can be perceived as a throbbing or pulsating sound, which is characteristic of beats.

Understanding beats is crucial in music and acoustics, as they can affect tuning and can be used to identify the difference in frequency between two notes. Unlike resonance, which involves the amplification of a single frequency due to an external periodic force, or the Doppler Effect, which relates to the change in frequency of sound due to the relative motion of the source and observer, beats specifically arise from the interference of two close frequencies.