[Bell Historians] Chiming Profiles

[Carl S Zimmerman]

David Bryant asked a very good question:
>Does anybody know when Taylor's developed their 'chiming profile',
>whereby the front bells of a chime are lighter than those in a ring?

[Bill Hibbert has beat me to the punch, but I'll send this anyway, 
because it adds to the discussion of the topic.]

One might also ask the reverse question, for which the answer 
presumably is a much earlier date (or decade): When did English 
bellfounders develop the use of a variable profile for bells to be 
hung for change ringing, to minimize the difference in weights 
between the treble and tenor bells of a ring? (or, alternatively, to 
minimize the differences in the volume of sound produced across the 
range of a ring.)

Both of these questions are intimately tied to a well-known property 
of European bells: The characteristic frequency of the bell's 
vibration is inversely proportional to the inside diameter of the 
bell at the soundbow, which is where the clapper strikes it (or 
should do). Since doubling the frequency of a sound has the effect 
of raising the apparent pitch by an octave (as our ears tell us), it 
follows that if two bells are an octave apart, and made to the _same_ 
profile (proportionately), then the smaller will be half the diameter 
of the larger. And because a bell is a three-dimensional object, the 
weight (mass) of the smaller bell will be 1/8 of the weight (mass) of 
the larger. (Equivalently, the ratio of tenor weight to treble 
weight would be 8:1.)

As an example, one might take the Taylor carillon and Whitechapel 
ring that were installed in Washington National Cathedral in 1964.
Ring: tenor D1 = 3588 lbs, D2 = 712 lbs, ratio 5:1
Carillon: D1 = 3470 lbs, D2 = 530 lbs, ratio 6.5:1
Theoretical: D1 = 3520 lbs, D2 = 440 lbs, ratio 8:1

Unfortunately I don't have details from the earliest modern English 
carillons. But it is well known that both Taylor and G&J, in their 
first "large" (over 3 octaves) instruments in the late 1920s, had 
very small, thin trebles, which sounded very weak and short-winded. 
All of the modern carillon builders learned from that and went back 
(each in their own way) to the concept of heavier trebles, though 
never to the degree that's used for change ringing bells. (You can 
see that in the example above.)

To answer Bill's question, the first set of modern harmonically-tuned 
bells to be exported to the USA was the 10-bell chime which Taylor 
made in 1898 for what is now Iowa State University. That chime was 
later enlarged (in three separate stages, 1929-1967) to produce the 
present 50-bell carillon. So far as I know, none of the older bells 
were ever replaced or retuned in the course of the enlargements, and 
this instrument has a long-standing reputation of being very fine. 
(See http://www.gcna.org/data/IAAMESIS.HTM)

I don't yet know enough about any of the chimes in the UK to be able 
to say whether any of them were predecessors of the Iowa chime.

Carl Z

P.S. I'm not hyphen-ated, though on occasion I might be pixelated.