The Sound of Bells

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The re-discovery of true-harmonic tuning

In preparation for a Central Council talk on bell sounds planned for September 2019 I have been revisiting the history of tuning standards, and in particular the work of Mears and their competitors in the late 18th and 19th centuries. Investigation into the tuning figures of bells of the period shows that although the Mears foundry was commercially successful, the competitors they acquired or put of out business – William Dobson in particular - were much better at casting musical-sounding bells than they were.

True-harmonic bells have their hum, prime and nominal in perfect octaves. The bell shapes and tuning methods needed to achieve this were first discovered by the Hemony brothers in the 17th century in the low countries. The skill was lost on their death, and re-discovered in the late 19th century by Taylors, assisted by Canon Simpson. Bells which are not true-harmonic usually have flat primes and sharp hums. This type of bell is known as old-style. It is a matter of taste, but most listeners prefer true-harmonic partials, especially in smaller bells.

At this period in UK bellfounding partials other than the nominal were not tuned. The Rudhalls had a tuning machine but this was used solely to tune nominals, to ensure bells in a peal were in tune with each other, but not correct the partials in an individual bell. The other founders relied on hammer and chisel, or files, to tune nominals. So the tonal quality of bells of this period relies entirely on the shape of the bell, the foundry’s strickles and the skill of the moulder.

William Mears, the first member of the family to be a bellfounder, cast his first bells in 1777 and then became proprietor of the long-established bellfoundry in Whitechapel. Elphick says about Thomas Mears junior (William’s grandson) ‘He had almost the monopoly of bellfounding as indicated by the enormous number of bells he cast . . . as the business expanded he bought up the smaller foundries . . . in 1825 he acquired the Aldbourne foundry in Wiltshire, then under James Wells . . . in the same year he took over the foundry at Hertford owned by John Briant . . . In 1830 Thomas acquired the great Gloucester foundry of the Rudhalls . . . Finally in 1833 he took over the foundry of William Dobson of Downham Market, Norfolk.’ Although not an acquisition and in an earlier generation, the Knight foundry of Reading moved to London in the early 18th century, was run latterly by Robert Catlin and Thomas Swain, and closed in 1781, just as the expansion of the Whitechapel business began.

Mears bells of this period are old-style, and many of their peals are tonally poor, for example St Luke’s Chelsea of 1824, St Barnabas Pimlico of 1849 and the old peal at Taunton with dates from 1816 to 1922. To compare the tonal quality of bells from Mears and the foundries they replaced, I took the average deviation from true-harmonic of the primes and hums for bells from these foundries. The results, in cents or 1/100ths of a semitone, are as follows:

FounderNo. of
bells
Earliest
date
Latest
date
Average
hum
Average
prime
Hum
Std Dev
Prime
Std Dev
Dobson481808182813.4-30.839.355.8
Briant361794182558.8-156.947.795.8
Knight / Catlin831575174863.8-38.659.275.7
Wells181770182690.3-57.956.383.0
Rudhall3101685183599.0-73.361.489.5
Mears before 185127717831850130.8-125.959.285.3
        
Taylor after 18951255189620180.6-2.010.111.5
Whitechapel after 192648119272012-1.5-1.19.16.5
Hemony5216511668-0.90.34.06.4

For comparison, I have included bells from Taylors and Whitechapel after they started true-harmonic tuning (excluding any bells cast as old-style), and the Hemony brothers.

In the table, the number of bells is the number of recordings from that founder in my collection, together with the earliest and latest dates of the bells. The average hum and average prime columns give the average deviation of those partials from true-harmonic. Positive deviations are sharp, negative deviations are flat. For example in a Dobson bell, the hum is on average only 13/100ths of a semitone sharp of the double octave. I have also given the standard deviation of the hum and prime tuning from true harmonic, to give an indication of how closely the founder was able to control the partials in each bell.

The founders in the upper part of the table are listed in increasing order of the discrepancies in the hums. Dobson is clearly the best both for hums and primes. Example Dobson peals are St John, Peterborough of 1808, Poole of 1821 and Wisbech of 1823. Briant is next best for hums but his primes are very flat. The average deviations for all five founders are all very much better those for Mears, apart from Briant’s primes. The clear conclusion from these figures is that although Mears were commercially very successful, the foundries they acquired and closed were all much better at producing good-sounding bells than they were. In the lower part of the table the quality of bells from Taylor and Whitechapel is clear, their average hums and primes are very close to true-harmonic and the standard deviations are much less because the bell shape is better and the hums and primes are tuned. In the case of the Hemony bells the accuracy of the tuning is very good, the hum and prime only have a spread of 4 to 6 cents – but then these are carillon bells for which accurate tuning is needed. The Hemonys had a tuning machine and tuned multiple partials, and of course with these older bells only the best have survived.

Four of the six bells at Fittleworth in Sussex where Canon Simpson was the incumbent and did his initial investigations are Mears (1824, 1884 and 1885) and the front 5 have typically sharp hums and flat primes. As he says in his second paper
"Sitting in my dining-room, with outer and inner doors shut, I was struck by the singularly sweet sound of our six little Fittleworth bells as heard down the chimney. On opening the doors, so as to hear them directly, I observed with surprise that the scale was different; and I finally discovered that what I had heard down the chimney were the hum-notes, which alone found their way, to me by this devious course".
I wonder if he would have done his investigations and written his papers if his church had had a Dobson six instead? Dobson was very close indeed to solving the true-harmonic puzzle 70 years before it was finally solved by Taylors.

References:
Sussex Bells and Belfries, George Elphick, Phillimore, 1970 (pages 108, 109 and 136-145)
On Bell Tones II, Canon A B Simpson, Pall Mall Magazine Vol. X pp 150-155.

Bill Hibbert
Great Bookham, Surrey

Last updated June 22, 2019. Site created by Bill Hibbert, Great Bookham, Surrey