I have actually seen (and played) the NBC instrument ( it had three notes) so this ain't it (and the NBC one had N B C on the three plates (in the right order).

So... My guess is that its from a mechanical music player like they have at the Musee Mechanique that used to be at at the Cliff House in San Francisco  http://www.museemechanique.org/   http://www.museemecaniquesf.com/  Now its at Fishermans Wharf.  Be sure to play the video of Laughing Sal http://en.wikipedia.org/wiki/Mus%C3%A9e_M%C3%A9canique


Bob


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Drew meyer
Sent: Thursday, December 30, 2010 12:57 PM
To: [log in to unmask]
Subject: Re: [TN] NTC: RE: Photo submission for quizzical minds.

Steve, Craig,

As has been stated the NBC was three notes.  The device will produce four notes.  Since it appears that the notes produced would be in human audio range.  I am going to guess a tuning device for a stringed instrument.

Tuning instruments that can produce sustained tones, beats can readily be recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not yet identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. When the two tones gradually approach unison, the beating slows down and disappears, giving way to full-bodied unison resonance.

Beat frequency tuning was the old human ear method but it requires a standard device of correct frequecy.

Drew Meyer

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