Comment by eyeonthescreen on March 11, 2010 at 10:44 am
Beats stem from frequency differences.
Compression waves, like musical notes, superpose on each other to give a resulting wave; as in f = f1 + f2; where f is the resulting wave frequency and f1 and f2 are two frequencies played by instruments 1 and 2. The beats you hear are the frequency of the resulting wave f.
When f1 <> f2, you will hear the beats because f1 - f2 = f <> 0. But when f1 = f2, you will not because f1 - f2 = 0 = f.
BTW: Beats are also used to sync two aircraft engine rpms. If the two propeller driven engines are in sync, there will be no beats because the rotation frequencies are equal. [See source.]
One comment
Comment by eyeonthescreen on March 11, 2010 at 10:44 am
Beats stem from frequency differences.
Compression waves, like musical notes, superpose on each other to give a resulting wave; as in f = f1 + f2; where f is the resulting wave frequency and f1 and f2 are two frequencies played by instruments 1 and 2. The beats you hear are the frequency of the resulting wave f.
When f1 <> f2, you will hear the beats because f1 - f2 = f <> 0. But when f1 = f2, you will not because f1 - f2 = 0 = f.
BTW: Beats are also used to sync two aircraft engine rpms. If the two propeller driven engines are in sync, there will be no beats because the rotation frequencies are equal. [See source.]