[Bell Historians] bell shapes

[Carl S Zimmerman]

I concur with David Bryant's remarks about different bellfounders 
having different profiles. From what I have seen in American bells, 
European carillons and assorted photographs, most foundries develop a 
profile which produces a sound that they like, and then stick to it. 
This is a major part of what makes it possible to hear the difference 
between carillons from different makers, for example. Accuracy of 
tuning the principal partial tones is only part of the job; different 
profiles will produce different relative strengths of those partial 
tones as well as different rates of decay, all of which contribute to 
the overall sound which we hear. Different profiles contribute to 
those factors.

It's true that there's a lot more variation in profile between makers 
who didn't tune their bells than their is between makers who do tune 
their bells. I know of one American foundry which produced wildly 
different shapes depending on the intended use of the bell--their 
steamboat bells don't look at all like their church bells of the same 
weight. But frequently I can identify the maker of a single church 
bell by its silhouette in an open belfry or bell-cote.

There's less difference between makers of tuned bells because the 
physical principles behind modern tuning require certain inside 
proportions, and that in turn places some limits on the range of 
outside profiles that can be used. Still, variations in height and 
thickness can be used to compensate for the basic scaling with pitch 
that is imposed by the laws of physics and vibration.

The reason that there is a difference between a ringing profile and a 
chiming profile has very little to do with the purpose to which an 
individual bell is to be put, and everything to do with where that 
bell falls into the range of a particular instrument in which it will 
be used. A bell which is to be the treble of a very deep-toned 
("heavy") octave will be much heavier than a bell of the *same* pitch 
which is to be the tenor of a higher-pitched ("light") octave. 
Another bell of the same pitch which is to be used in a chime or 
carillon will fall somewhere between those two ringing bells, because 
it has to be part of a practical series that covers much more than an 
octave. Unfortunately, it isn't possible to show this graphically 
within the plain-text limitations of email, and I don't know of any 
Webpages which do that. (I'd be delighted to be proven wrong!)

For these reasons, bellfounders who produce tuned change-ringing 
bells, as the two surviving English founders and Eijsbouts do, must 
have in hand a much wider range of profiles than those who only 
produce single bells, small peals, or chimes and carillons.

By the way, it is over-compensation in a profile series which results 
in the peculiar situation we sometimes find in non-homogeneous rings, 
wherein the treble is actually heavier than the deeper-toned second 
bell.

CSZ