Two sounds have frequencies that are too close together. There is interference and they create a third sound that isn’t too pleasant. is this Beat Frequency, harmonics, or resonant frequency.
This is beat frequency. Beat frequency occurs when two sound waves with slightly different frequencies interfere with each other, creating a new frequency equal to the difference between the two original frequencies. This new frequency can create a "beating" or pulsating sound that is less pleasant to listen to.
