The Sound of Bells

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Hilmarton, Wiltshire, St Laurence, 6, 15 cwt in E

Recorded: Dave Kelly 5/5/00
Analysed: WAH 27/10/01

This old-style six consists of bells from a range of founders and dates. They are hung in a two-tier timber frame with all bells swinging east-west. Retuning of the bells is being considered and I was asked by the tower captain, Ken Webb, to analyse the bells. The recordings of the individual bells were kindly supplied by Dave Kelly of the Keltek Trust. Here is a recording of all six bells being rung in rounds.

Bell Founder Tuning
1 Mears 1875 none since
2 W & T Purdue 1652 Chip-tuned 1885 by Alfred York, Bristol
3 R Purdue?? 1631 none since
4 Bristol 1450 none since
5 Rudhall 1735 none since
6 Rudhall 1738 Chip-tuned

Tuning of main partials

Tenor nominal: 649.4 Hz

Bell Hum Prime Tierce Quint Nom'l S'quint O'nom. Founder
1 -2221 -1275 -859 -319 968 671 1205 Mears 1875
2 -2413
-2406
-1360
-1376
-910
-912
-528 721
719
711 1260 Purdue 1652
3 -2397 -1199 -886 -482 515
524
679 1221 Purdue?? 1631
4 -2311 -1291
-1297
-878 -494 427 683 1233 Bristol 1450
5 -2371 -1150 -890 -481 174 700 1256 Rudhall 1735
6 -2253 -1164 -879 - 0
-2
694 1246 Rudhall 1738

(The figures in this table are all given in cents. For all partials except the nominal, the partials are given from the nominals of the bell. Cents of the nominals are relative to the tenor. Pairs of values indicate a doublet. Frequencies for the quint are often not given, especially if inaudible. The links in the first column provide recordings of all the bells.)

Intensity plots

Here are intensity plots for all six bells:

Hilmarton treble

Hilmarton second

Hilmarton third

Hilmarton fourth

Hilmarton fifth and sixth

Commentary

This peal contains much of interest, both good and bad. As is clear from their provenance, tuning and sound, there are five quite different styles of bell in the peal - I class the 5th and tenor together. Considering each bell in turn, the treble has the typical old-style tuning for its founder and date. The hum is quite sharp but the prime is not as flat as it might be. What makes this bell rather pleasant to listen to is shown by its spectrum. When chimed, it has a very strong nominal and almost no prime. I quite like the tone of this bell.

The second is not at all a pleasant bell. It has a slightly flat hum and a strong, very flat prime and has large doublets on all its important partials. I understand that the exterior of this bell is a rough casting, which probably explains the doublets.

The third, if it really has not been tuned in modern times, is a considerable tribute to the ability of founders in times gone by. The tuning of its five low partials would not disgrace a founder of today. It has very muted high partials, but interestingly has a prime which is much stronger than its nominal. There is a class of 'Continental' bells which are pitched by the prime rather than by the nominal. Simpson thought this was an error, but in a bell like this we can see why it might be the right thing to do. Unfortunately, this bell is spoilt by a wide doublet on its nominal which slightly mars its tone.

The fourth is a venerable bell indeed - still in use after 550 years. Its main partials are rather better than those of the Mears bell cast 425 years later. I have rung a number of these 15th century Bristol bells recently and they are all quite pleasant. Before extolling too strongly the virtues of this anonymous founder, of course I should point out that for a bell to have survived this long in a ringing peal suggests either reasonable tone or a great degree of affection. The really bad bells of this date were broken up and recast centuries ago! This bell is spoilt a little by its flat, doubletted prime being almost as prominent as its nominal. This causes its perceived pitch to drop by a semitone and warble as the nominal dies away. This effect would not be noticeable in changes.

The fifth and sixth are both pretty typical bells of their age and founder. Their primes are good, if slightly sharp, and the hums are pretty respectable, especially in the fifth. The quietness of the primes and hums in these bells compared with the nominals helps their tone.

The most striking thing about these bells considered as a peal is the errors in their nominals. Listening to them rung in rounds, the fifth is plainly rather flat and although not initially as noticeable, the treble is sharp. I understand that the treble was supplied in 1875 without the other bells being removed from the tower, which might explain the error in its pitch. The second was sharpened about 10 years later, which has disguised the error in the treble somewhat, but has actually compounded the problem. In its current state, the peal is definitely less than the sum of its parts. The plot below shows the errors in each bell's nominal from equal temperament. I chose equal rather than a tuning with softer thirds because the fourth bell (the third of the musical scale) is the second sharpest bell in the tower. The plot shows just how scattered the nominals are.

Hilmarton nominals

Retuning

I was asked by the tower captain for my views on the retuning of these bells. Below, I suggest some ideas that might be taken into consideration. The objectives if retuning of these bells were contemplated should in my view be as follows:

The historical interest of some of the bells dictates the tuning strategy. The fourth ought not to be touched if possible. The treble, fifth and sixth can be tuned at will, as bells of these ages and founders are very common. One cannot really object to tuning the second, as it has already been chip-tuned in the 19th century. The third could also be tuned, but the great accuracy of the lower partials in a bell of this date is of interest. On the other hand, to attempt to lessen the doublet in this bell would be no bad thing. Flattening bells is somewhat easier than sharpening them, but the details of a tuning plan depend on availability of metal in the bells, which I am not able to assess. To accommodate these constraints, I have suggested several approaches.

The biggest issue in tuning the nominals is the gap between the fourth and fifth, which is 243 cents or nearly half a semitone too wide. The fourth cannot be tuned down, so if it is to be preserved in the ring, the fifth has to be tuned up. Unfortunately the fifth is the better of the two Rudhall bells.

The first scheme I suggest only involves sharpening the fifth, and flattening the treble. If the metal exists, the fifth has to go up by 40 cents and the treble down by 43 or so, giving nominals from treble to tenor of 925 cents (tuned), 721/719 (not tuned), 515/524 (not tuned), 427 (not tuned), 214 (tuned) and zero (not tuned). The other partials in the treble and fifth could be tidied up at the same time. I suspect this would remove most if not all the out-of-tune effect of the nominals which would be a definite improvement. None of the oldest three bells are tuned in this scheme.

The second scheme, which builds on the first, would involve tuning the second, third and tenor also, and further sharpening the fifth. The aim would be to address the doublets in the second and third, and pull the nominals further into line. The deciding factor here is whether the tenor can be sharpened (and the fifth further sharpened) while not spoiling their tone. If the metal exists to do this, the tenor nominal should be tuned up 25 cents or so, the fifth by a whole 50 cents, and the third and second have their nominals tidied up to be at the pitch of the higher of the doublet pair. As before, the treble nominal should come down by 40-odd cents. If such changes were possible, this would give a peal in effect tuned in equal temperament. The oldest bell would not have been tuned, and the next two oldest would not have had their pitch changed by any great degree but their tone would have been improved. However, the two Rudhall bells would have been tuned up, which might not improve them.

The last scheme would be to replace the fourth with a new or second-hand bell which could be tuned. This would then allow the nominals in the whole ring to be tuned down, which is a much more practical proposition. The treble though has to come down by 60 or 70 cents to achieve this. I do not doubt but that this ring would then be musically much better - in particular, if there is enough metal in them, the tone of the two Purdue bells would be improved by the tuning. However, this would completely destroy the historical character of the ring. Whether this is desirable is a matter of judgment.


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Last updated October 31, 2001. Site created by Bill Hibbert, Great Bookham, Surrey