[pianotech] Tuning fork puzzle

[John Delacour]

This afternoon I was planning an experiment today and messing about 
with a tuning fork, a board and various things in between.  Listening 
for all sorts of things I realised that I was hearing the octave of 
the fundamental very strongly.  In several situations the octave 
sounded almost as strongly as the fundamental, sometimes equally 
strongly, and in some cases, for example when holding the fork near 
the top of the long bridge, the octave prevailed significantly over 
the fundamental.

Now I am told that the first overtone of a tuning fork has about 6 
1/4 times the frequency of the fundamental, so where is this octave 
coming from?

JD