[Bell Historians] Using tuning forks.

[Carl S Zimmerman]

Steve Ivin wrote:
>The point about tuning forks is really that their use requires
>_ears_, except perhaps by the method used by A B Simpson, involving
>resonance i.e. touching the bell with the fork.

and

>It is not completely established that the pitch when the bell is
>'driven' by the probe is exactly the same as the bell struck with a
>clapper however.

Although I don't pretend to have any answers in this debate, I think 
it extremely important that we make sure to use common terms of 
reference, and not to compare things which are not comparable. These 
two points which Steve has raised are significant steps in the right 
direction.

To say without qualification that tuning forks either do or do not 
measure the same things as electronic frequency measurement devices 
makes no more sense than to say without qualification that yardsticks 
and tape measures either do or do not measure the same things. For 
statements of this kind to be true, one _must_ qualify them (either 
explicitly or implicitly) with respect to how the things are used and 
what is being measured.

For example, a bespoke tailor may well use both yardstick and tape 
measure, but the latter is the tool of choice to measure the 
customer, while the former would probably be the tool of choice to 
measure the fabric (sometimes called "yard goods"). There is no 
inconsistency in the use of two different measuring tools because 
both are calibrated to the same standard (probably inches :-).

With respect to sound, the standard of calibration is the unit called 
Hertz (abbreviated Hz), formerly known (and still defined) as cycles 
per second (abbreviated cps). I'm quite confident that both tuning 
forks and electronic frequency measuring devices (EFMDs, to coin a 
term) can be calibrated to this standard. Then the question of 
whether these two kinds of devices have produced or can produce the 
same results in the tuning of bells really becomes a twofold question 
of (1) whether they have been or can be employed in the same way, and 
(2) what we mean when we say "same results".

Up until now, most of the discussion has really been related to the 
second part of that question. Opinions have ranged all the way from 
"According to my ears, none of the EFMD-tuned bells sound as good as 
the best of the fork-tuned bells" to "Forks and EFMDs are both used 
with the same set of Simpson-principle frequencies, so the results 
must be the same". I would venture that the silent majority are 
sitting in the middle, scratching their heads over this, and 
wondering which way to lean. (Or perhaps they just hit the Delete 
button and head for the nearest pub for some liquid relief.)

But to make more sense of this all, I think we need some 
well-informed contributions from people who can expand on the points 
which Steve has raised. How are forks and EFMDs actually used? i.e., 
how is the bell forced to produce the vibration which the fork or 
EFMD measures? Has anyone ever done experiments to compare tuning 
fork methodologies with EFMD methodologies? In what specific respect 
is any one of these methodologies either superior to or inferior to 
another of these methodologies? Which methodologies require the use 
of the human ear, and how do they compare with methodologies which 
don't? What about transient frequencies versus resonant frequencies? 
etc. &c.

I look forward to reading contributions from those subscribers who 
know far more about these things than I do.

Carl