Question

To tune a violin, the violinist first tunes the $A$ string to the correct pitch of $440Hz$ and then bows two adjoining strings simultaneously and listens for a beat pattern. While bowing the $A$ and $E$ strings, the violinist hears a beat frequency increases as the tension of the $E$ string is increased. ( The $E$ string is to be tuned to $660Hz$.)
Why is a beat produced by these two strings bowed simultaneously?

Answer 1

When the two strings of a violin are bowed simultaneously they vibrate with different frequencies. When these two waves of different frequency approach our ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud that is producing characteristic pulsations, or throbs, calledbeats.