Good point.
See here
http://www.bluesblast.com/frequency.txt
I quote:
'The pitch of a note is almost entirely determined by the
frequency: high frequency for high pitch and low for low. For
example, 110 vibrations per second (110 Hz) is the frequency
of vibration of the A string on a guitar. The A above that
(second fret on the G string) is 220 Hz. The next A (5th fret
on top E string) is 440 Hz, which is the orchestral tuning A.
(The guitar A string plays the A normally written at the bottom of the bass clef. In guitar music, however, it is normally written an octave higher.) We can hear sounds from about 15 Hz to 20 kHz (1 kHz = 1000 Hz). The lowest
note on the standard guitar is E at about 83 Hz, but a
bass guitar can play down to 41 Hz. [(sic) - we know that is
not a correct generalization] The orginary guitar can play notes with fundamental frequencies above 1 kHz. Human ears
are most sensitive to sounds between 1 and 4 kHz - about
two to four octaves above middle C. Although the
fundamental frequency of the guitar notes do not usually go
up into this range, the instrument does output acoustic
power in this range, in the higher harmonics of the most of its
notes. '
See here for a general discussion But specifically see here for Even Tempered frequencies
I should bookmark that, it comes up all the time ...
