This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Hi again... <<I have attached a small jpg to this message. You can see a small = piece of the waveform of the file I made. The left part is the 20kHz = tone, then the 20.5kHz tone is added. The amplitude modulation you can = see (which is another way to look at beats), when put into the air, is = moving the air in a pattern of a 500Hz sine wave - just what one hears. = It is my opinion that, even though the two high tones themselves are not = easily audible in this test, the amplitude modulation of the tone at = 500Hz becomes audible on its own.>> Amplitude modulation is an entirely different beast. It looks *similar* = and has similar properties, with one very critical exception: Amplitude = modulation is a nonlinear process that creates heterodyne bands (i.e. = scattering energy to new frequencies). Beating from = destructive/constructive interference is a linear process that does not = create spectral scattering. Amplitude modulation is multiplicative, not = additive. A classic example of amplitude modulation is Anderson (from = Jethro Tull) singing into his flute. Another classic example is = "ooting," the practice of humming while whistling. These sounds are = very "strange," and one can easily hear the spectral scatter. Peace, Sarah ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/7b/e9/b6/e6/attachment.htm ---------------------- multipart/alternative attachment--
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