Well, I didn't quite find what I was looking for... but in the 1930/40's, the USA had a radio station (WWV) that actually added the output 440Hz for use in calibration. see the following: http://en.wikipedia.org/wiki/Pendulum http://tf.nist.gov/timefreq/general/pdf/1485.pdf http://en.wikipedia.org/wiki/Tuning_fork http://www.youtube.com/watch?v=V-kRShXR6qA Bill Fritz, St Louis From: Terry Farrell <mfarrel2 at tampabay.rr.com> To: pianotech at ptg.org Subject: [pianotech] Tuning Fork Standard Date: Thu, 20 Jan 2011 20:10:26 -0500 Prior to electronics - let's say more than 100 years ago - or even 150 years ago - what was used to calibrate a tuning fork? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20110120/ac1ae0ea/attachment.htm>
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