[Bell Historians] PItch of bells

[jimhedgcock]

--- I hope that the book about G&J will be publicised in RW. It will 
be of interest to many.

In bellhistorians at yahoogroups.com, Carl S Zimmerman <csz_stl at s...> 
wrote:
> A very timely question & answer! Last Saturday, the post-Congress 
> (think AGM) tour of the Guild of Carillonneurs in North America 
> visited the World Peace Bell in Newport, Kentucky. As you probably 
> know, it is the world's heaviest swinging bell. The reported pitch 
> is very slightly sharp of A, an octave and a third below middle C. 
> But to my aging ears, the predominant frequency appeared to be D 
> above middle C, an octave and a fourth above the strike tone. In 
> fact, this virtual pitch seemed to be so strong that I could only 
> distinguish it and the strike tone, not any of the other partial 
> tones which should have been in range--very strange!
> 
> It occurs to me that this same phenomenon may have been the cause 
of 
> the problems which Cyril Johnston had in casting the bourdon for 
> Riverside Church in New York City. At the Congress, Jill Johnston 
> read to us a chapter from her forthcoming book about her father and 
> his work. She related how Frederick C. Mayer, carillon consultant 
to 
> John D. Rockefeller Jr. on that project, rejected the first and 
> second castings because the bells had a predominant fourth instead 
of 
> the desired minor third. Ultimately the third casting was also 
> rejected, and the project reverted to the first casting, which now 
> hangs in Riverside Church. The turmoil of those rejections took 
its 
> toll on Cyril Johnston, and it was during this time that Jill was 
> conceived. I'll leave the rest of that fascinating story to Jill 
and 
> her book. But it is interesting to speculate whether Mayer was 
being 
> deceived by his own ears, and whether a modern frequency analysis 
(a 
> la Bill H) would have given different results and saved Cyril some 
> major headaches.
> 
> Returning to the World Peace Bell, what you probably don't know is 
> that it weighs considerably more than the 66,000 lbs which has 
> heretofore been advertised. That story, as told to me by Philippe 
> Paccard, is also fascinating. It seems that at the time the WPB 
was 
> being planned for completion to ring in the new millenium, another 
> project for the "world's largest swinging bell" was being bruited 
> about Paris. To finesse that, Verdin and Paccard gave out that the 
> WPB was being planned for 30 metric tons (about 66,000 lbs), but 
> actually they were planning for 33 metric tons. In the end, the 
> Paris project fell through, and the finished WPB (hung as cast, 
> untuned) weighed out at 33385 kg (slightly over 73,000 lbs) before 
> shipping. With clapper and yoke, the total swinging weight is 
about 
> 104,000 lbs.
> 
> Incidentally, the clapper of thw WPB is a story in itself. The 
> original (and extremely grandiose) plan was to hang this bell at 
> about 200 ft altitude in a 2000 foot tall tower, surrounded by a 
> 90-bell carillon. It would have had the conventional falling 
> clapper, and would have been audible for about 20 miles. However, 
> the escalating cost of all aspects of the project meant that the 
> planned tower wasn't built, and the WPB is hung only 35 feet above 
> ground in a very squat structure. To use a falling clapper at this 
> low altitude would have caused major damage to the hearing of 
people 
> nearby, so Paccard switched to a counterbalanced "flying" clapper. 
> With the counterbalance, the weight of this assembly is about 6 
tons. 
> When the swinging motor is turned on, the clapper begins to strike 
> after only 6 oscillations, and the bell swings up no more than 45 
> degrees in either direction. It is so well balanced that after it 
> stops sounding (but keeps swinging), a visitor on the viewing 
> platform can give it a push (quite safely, I assure you!) to make 
it 
> strike once more. By the way, WI enthusiasts will be pleased to 
hear 
> that this clapper is made of wrought iron. Paccard had great 
> difficulty finding in France an ironworks with large enough forge 
> capacity to make it; such firms are about as uncommon as 
> bellfoundries these days.
> 
> After leaving the WPB, we visited Verdin's factory in Cincinnati, 
> where thay had made the drop hammer by which this bell can be 
tolled 
> (cast iron semi-conical hammer head made by a subcontractor), and 
> finished the tour at the bellfoundry of Meeks & Watson, where we 
saw 
> two small carillon bells being cast. But that's a story for 
another 
> time.
> 
> 
> At 08:27 +0000 2003/06/24, Bill Hibbert wrote:
> >Chris Pickford:
> >
> >> "why can one always hear a strong fourth in big bells?"
> >
> >This is a virtual pitch, not a real partial, and arises because the
> >ear is presented with several harmonic series and picks out one 
based
> >on a harmonic higher than the nominal. The reason why we hear big
> >bells, normal-sized bells and little bells differently is down to 
the
> >ear's differing sensitivity to different frequencies. Ears are most
> >sensitive to frequencies from about 1 kHz to 3 kHz and so we tend 
to
> >hear a note between 500 and 1500 Hz, roughly, whatever the size of
> >bell, if there is a harmonic series present to give a suitable
> >virtual pitch.