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ps.com...
On Jul 6, 6:08 am, "N Cook" wrote:
For 5 octaves , for the "white" notes only , is the 15 th key from the
left
middle C ? . Without any pitch-bend should it be 256 Hz or 256.?,262,
264 ?.
Or should the calibration be on "A" above middle C ie white key number
20 ?
and should that be exactly 440 Hz or some other frequency rounded to 440
Hz
?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list
onhttp://home.graffiti.net/diverse:graffiti.net/

If you're working with an equally tempered scale, A above mid-C would
be 440Hz and middle C 261.625. The relation is 12th root of 2, approx
1.059. And yes, there are people who demand .01Hz or better accuracy.
Wikipedia is a good place to start.

http://en.wikipedia.org/wiki/Equal_temperament

GG


Thanks for that , its not a well tempered clavier or anything ancient but a
late 20C electronic keyboard. So I take it that middle A reading 440.000 +/-
a little on a crystal controlled frequency meter then middle C should read
261.625 +/- a little.
Over the years I've come across a couple of people who've professed to have
"perfect pitch" and I've asked them what it was like listening to films like
Amadeus or Farinelli on TV and they've both not reported any problems
despite AFAIAA 24 frame per sec film is shown at 25 frame per sec on UK TV
telecine so a 4 per cent frequency shift, whatever that is in semitones.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/