Tuning fork inharmonicity

[ed440@mindspring.com]

Ric wrote:

Ed. You do bring up something at the end of your post that is alarming 
if true.  You seem to hint at high degrees of inharmonicity in pitch 
forks... para inharmonicity at that.  If it is indeed true that the 
second partial of pitch forks is as wildly irratic as you state.... then 
its an unreliable pitch source to begin with.  If so... well we are in a 
whole new ballpark.... I'll be the first to agree on the need for a 
reliable pitch source.

I respond:

I think the accuracy of a fork at its fundamental is good, especially if the temperature is controlled.
Ellis, in the 19th century got very accurate readings by only striking the fork once a day, because striking the fork and letting it vibrate raised the temperature and changed the pitch!  That is more accuracy than we need.
As to the second partial of the fork: Most texts give the second partial as about 6 times the fundamental.  That is the little high "ping" you hear when you first strike the fork.

Yet Ellis reports hearing something at 2 times the fundamental when he held the fork over a resonator at that pitch.

I don't really know what it is we hear at 880hz from a 440hz fork.  Is is something the fork is doing, or is it an artifact produced by our ears?  

Both Accutuner and Cybertuner Pianalyzer report something at 880hz (very, very weak on the Pianalyzer intensity scale).  Is this from the fork, or a microphone produced artifact?

So I don't really know what we are hearing.  I can tell you that Cybertuner Pianalyzer gave very inharmonic, very variable readings at 880hz (forks held in the air, by the way).

We may be hearing something different when playing F3 to the fork.  The beat I hear there is weaker ("shimmering") than when I play F2 to the fork.

My sources are Helmholtz, Benade, Backus and Hall 1980.  Perhaps someone can tell us of more recent rersearch.

Until then, like you said, use your Accuvericyberlab for the most accurate pitch setting.

Best wishes,
Ed S.