The effect of tuning collars on pipe tone

[petergunstone]

I have been watching Peterborough Cathedral's 'PipeWatch' series of youtube films concerning the current work to lower the pitch of the Hill Organ. See https://www.youtube.com/channel/UCjzMmoV88eTR5LOKknv7UNQ/videos

 

In the most recent of the series, 'Meet the organ builders' (https://www.youtube.com/watch?v=wdSFNc_e57g) I was interested to note that some of the smaller pipes (1ft in length or less) will not need to be lengthened, but may be retuned to the new pitch simply by using the tuning collar.

 

It seems to me that there are clear pragmatic, tuning reasons for not employing this approach throughout the organ. I do wonder, however, what the effect tuning collars have on the tone of an organ pipe. I understand that the scale of pipe construction has some effect on the tone of the pipe, clearly demonstrated between distinctly narrower and wider pipes. But what of the different material that tuning collars seem to be made from?

 

Taking the discussion further, does cone tuning also have an effect on pipe tone as this does change the shape of the column of air?

 

I suspect that the answers may involve subtleties, but aren't we often interested in such subtleties and their musical ends? I look forward to reading your reflections on all of the above, and any else that seems relevant to this discussion of pipe construction, tuning, and tone.

[sprondel]

It seems to me that there are clear pragmatic, tuning reasons for not employing this approach throughout the organ. I do wonder, however, what the effect tuning collars have on the tone of an organ pipe. I understand that the scale of pipe construction has some effect on the tone of the pipe, clearly demonstrated between distinctly narrower and wider pipes. But what of the different material that tuning collars seem to be made from

 

Taking the discussion further, does cone tuning also have an effect on pipe tone as this does change the shape of the column of air?

 

I suspect that the answers may involve subtleties, but aren't we often interested in such subtleties and their musical ends? I look forward to reading your reflections on all of the above, and any else that seems relevant to this discussion of pipe construction, tuning, and tone.

 

Both cone and collar tuning should have minimal effect on tone, if properly applied. That includes the desired pitch being not too far from the pipe as built, without the collar. An overlong collar will alter the scale, rendering the pipe as well as the cut-up narrower in relation to its length; among other things, speech might suffer. A pipe that is heavily cone-tuned will sound muted (lower) or unstable (higher). Additionally, pipes must be designed to withstand cone-tuning, e. g. by a metal sheet that is thicker near the lips than it is at the top, so that it gives way easily to the cone but keeps stable around the flue and tip.

 

As far as I know, steel is used for collars because of its being more springy than tin-lead alloy. I don’t know if there are any undesirable contact effects.

 

One of the most famous organs of all, the Freiberg Silbermann, is now collar-tuned as a consequence to long and heated debates on the temperament (or lack thereof) that was to be applied, the original tuning having been lost. This, of course, was done because collar-tuning is easily reversible.

 

All best wishes

Friedrich

[Colin Pykett]

As correctly mentioned above, the scale of any pipe whose length is increased by whatever means (i.e. collars or adding bits on), will be changed. This will alter its tone quality, which is strongly influenced by the retinue of natural resonant frequencies characteristic of the resonator. This happens because the natural frequencies are influenced by scale. They are anharmonic, i.e. they are not harmonically related, and the degree to which they amplify the corresponding harmonics generated at the mouth (which are exactly harmonic) largely determines the steady-state timbre of the pipe. Pipe scale determines the frequencies, amplitudes and Q-factors of the resonances because it affects the end corrections at the mouth and top.

 

Whether or not the change of timbre effect is large enough to be perceived, when the scale is only being modified slightly, is another matter.

 

I was interested to see the brief shot of the risk assessment document and, later on, the dirty hands of the organ builders. I have often wondered whether the dirt, which must contain an appreciable amount of lead, is a health hazard considering that they handle the pipes for many hours each day and every day during a job like this, and therefore whether it is taken into consideration when preparing the risk assessment. I once raised this with a retired consultant physician who is now a relatively well-known organist, teacher and organ consultant, and his view was that organ builders might consider wearing thin plastic disposable gloves. I have seen some who do this.

 

CEP

[David Drinkell]

I think the wearing of gloves is quite common in the trade these days.

 

With regard to cone tuning, I know of a modern small two manual by a Belgian firm in a Roman Catholic church which was originally coned, but later fitted with slides (and converted to Equal Temperament). The tuner (from the reputable British firm in charge) said that, in order to minimize damage through cone-tuning, the pipe tops should be thinner and therefore more pliable than the rest. This had not been done and, in a short time, the mouths had started to collapse. Forumites will know that, once this has happened, the metal is weakened and will collapse again. It was a nice enough little organ, but apart from the aforesaid problems with the mouths, I thought the tracker action was on the flimsy side - they had to get the tuner in to correct ciphers on the day of my recital. I couldn't help thinking that a home-grown product - such as our hosts produce, or someone like Neil Richerby (whose organ at Haddington near Edinburgh had me enthralled) - would have been more up to the job.