The organ statement has me interested. I have experienced standing waves in this way. Moving through a space with a stagnant/constant sound source will give you the pleasure of hearing certain partials as being louder in specific locations in the room. If you move through the space you are essentially animating this effect. Sine waves, which have no partials, will do the same thing, but that the sound will disappear in certain places in the room, so when moving through the space it will sound like beating. Doesn't doppler reference a change in frequency? Wether it is light or sound or some other set of frequencies? When I turn fans off when tuning I certainly do it because I hear "beats". But now I am curious if the sound waves are actually being distorted in the way that would compress and or expand the wave's structure resulting in a frequency change. So what we hear are perhaps not only amplitude changes based on the periodic reflection of sound, but ALSO a vibrato or pitch change because the reflecting surface is moving. hmmm Shawn On Sun, Jun 20, 2010 at 6:27 PM, Ron Nossaman <rnossaman at cox.net> wrote: > Don Mannino wrote: > >> Well, I'll take "Doppler shift of echoes" but not "from echoes." But >> you're >> right, it's nit-picking. >> > > You're right, "of" echoes. Hearing the source against the shifted echo > makes beats. Way back when, I noticed the same thing using a wedged down > organ key as a pitch source to tune the piano in a church. Walking back to > the piano, the organ tone beat at varying rates depending on how fast I > moved. I found that walking around outside with an Accu-Fork, I could hear > beats as I approached solid objects. Echolocation! I thought it was pretty > cool. > Ron N > -- Shawn Hansen RPT certified piano technician 816.896.4047 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100621/478c64dc/attachment.htm>
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