source file: m1548.txt Date: Thu, 8 Oct 1998 13:58:43 -0400 Subject: RE: Cancelling out beats From: "Paul H. Erlich" Paul H. wrote, >?? I must be misunderstanding something. If you analyze the signal >using a process which decomposes it linearly, such as a Fourier >transform, no energy is detected at the beat frequency. What is a >decrease from nothing? I think this is what Gary Morrison was talking >about when he said (talking about bram's beat-canceling idea): Reading this again, I note an even more important point: the ear does _not_ detect energy at the beat frequency; even beat rates in the audible range do not necessarily produce audible tones (they only can be said to do so if the conditions are right for difference tones: loud enough for the real nonlinearities of the ear to be inmportant), as Helmholtz observed. The beat is only a variation in the energy at an average frequency of the original waves.