Tuning and climate – a South African view
By R. W. Gould-King
Visiting pipers from Scotland often complain about our comparatively harsh South African climate. Many a piper from overseas has opened his pipe box in Johannesburg to discover the mummified remains of a once fine instrument. The initial reaction is to mutter a few lines from the Flame of Wrath in expressive canntaireachd, followed by a long battle with a rather desiccated instrument.
Visitors to Johannesburg outwith South Africa, can console themselves with the fact that pipers from our coastal areas seem to suffer a similar fate on arrival here, while those of us from the Transvaal who compete at sea level, have the opposite problem: catarrhal pipes.
The variability of the climate is therefore of prime importance to the piper who travels several thousand miles annually to compete for the various chromium-plated pots offered, while the piper whose main aim is to amuse at local parades is affected to a lesser extent. He grows accustomed to the diurnal and seasonal fluctuations of his town and, hopefully, tunes his instrument to suit. Quite often one hears a local piper say that his pipes are ‘flat’ at the coast while the opposite is true for a visitor from the coast at an inland event.
The purpose of this discussion is to examine the influence of our climate on the tuning of the pipe and to draw up some guidelines, if any. It is certainly better to be prepared for possible disconcerting conditions rather than strike up blithely on the day of the competition only to discover the worst at a critical time.
The frequency of a sound or note is a function of many variables and is generally satisfied by the relationship:
frequency = (velocity of sound)
Temperature, humidity and pitch
The velocity of sound in a perfect gas is a function of temperature only, thus in dry air at 68° Fahrenheit the speed of sound is approximately 1125 ft/sec and at -67° F the speed would be 972 ft/sec. The atmosphere however also contains water in varying degrees and at variable pressures which will have some affect on the velocity of sound and hence of frequency.
The velocity of sound is a function of the specific heat ratio, force of gravity, gas constant, the molecular mass of the gas and a number of other factors.
The main factors recognised by the average person as everyday values in terms of weather are the temperature, atmospheric pressure and relative humidity. The equations for the speed of sound, frequency, relative humidity and so on were programmed on a mainframe computer to yield the graphical representation below which shows the relationship between temperature, humidity and pitch, where the term pitch is used rather loosely here to mean frequency. For example, a tuning fork held away from the ear will appear to have a higher pitch than the same apparatus held near the ear.
The correct pitch scale is a subjective scale and is called a ‘mel’ from ‘melody’, and is defined: a sound with a frequency of 1 000 cycles per second at an intensity of 40 decibels has a pitch of 1 000 mels.
The graph below represents an instrument tuned at 68°F at a relative humidity of 25% and the line shown is for a frequency of 918 c/s:
Should the same instrument, without altering the setting of the chanter reed, be moved to atmospheric conditions represented by the range below the line then the pitch or frequency will increase, while above the line will result in a drop in pitch and a resulting ‘flat’ high A.
One can basically infer from this that, moving from Johannesburg to Durban, where relative humidity and temperature would be high, would cause a set of pipes tuned in the inland city to sound flat at the coast, especially in Winter when there is a sharp differential between the two climates: cold and dry versus warm and humid sub-tropical. The following page shows percentage deviations in pitch for the above conditions, and the amount of deviation can be clearly seen to be quite remarkable in circumstances.
Reeds harder to blow
While one may agree that the conclusions reached heretofore are correct, the actual affect of climate on the instrument itself has not been discussed. Thewinding of an instrument in a dry atmosphere will result in two facts:
(i) The pitch will be relatively higher because the velocity of sound increases as the water vapour content decreases and as temperature increases.
(ii) On a hot, dry day the reeds themselves will be harder to blow because they are dry) and will consequently have a higher pitch. However, the reeds absorb a certain amount of moisture from the breath and will eventually reach a state of equilibrium with incoming moisture compensated by evaporation. The pitch differential for tenor drone reeds between the start and final settling down stage is probably in the order of 1% or 5 c/s.
In such an atmosphere there will be a little moisture, if any, forming inside the reeds or drone bores as visible drops and constant blowing is virtually a necessity in order to keep the pipes in first class tone. With the use of water traps and moisture absorbing types of bag ‘seasoning’ the time taken to settle down to steady state can vary from 15 minutes to over an hour, depending on conditions at the time.
If the scale intervals given by Seumas MacNeill on page 26 of his excellent work on ceòl mòr are correct (and there is no reason to assume that they are not), then some simple arithmetic will show that harmonics exist for all the notes on the chanter scale, some particularly strong ones occur for the bass drone notably low A (4th), B (9th), C (5th), E (6th) and A’ (8th).
It is the rich tonal quality of the entire instrument that depends on the correct relationship of chanter and drones and it is therefore extremely important to tune the chanter so that the intervals are correct in relation to the scale and the drones. For example, an “‘in-tune” A – E combination and a slightly flat A’ will cause dissonance on the other notes and the overall tonal quality will be destroyed. This may be acceptable to some but it is not the stuff to send shivers up the spine nor is it doing justice to this finest of instruments.
Some pipers are known for the fine tuning of their instrument and I have heard it being said that, “So and So’s B is fantastic : every time he plays the drones seem to invert …”. Essentially, what the listener is hearing is the 9th harmonic which has to be heard to be appreciated.
Certain people have what is called perfect or absolute pitch and can tell where a frequency touches the basilar membrane as surely as we can locate a pain from a pinprick, while others are totally or partially deaf or insensitive to certain tones, and this latter problem will continue to plague piping appreciation for all time.
Control of moisture
While it may be generally conceded that some moisture on the chanter reed is desirable and this is usually achieved by the judicious application of saliva, as many a tobacco-stained reed bears mute witness, the presence of visible moisture on the drone reed is a sign of impending doom sometimes resulting in complete stoppage or a steadily increasing unsteadiness. As mentioned before, we depend on waterstops and special pipe bag concoctions to trap excess moisture.
The human being exhales a few pints of water every day and on wet humid days and after long periods of continued piping, a saturation point is reached in the pipe bag that results in precipitation on the reeds, up the drones and down the pipe chanter. The gradual accumulation of moisture in the drone bore will eventually result in a drop or drops running down the bore and into the reed and possible disaster if the drop strikes the tongue of the reed.
Two temporary solutions to this problem are to place blotting paper in the bore as shown in the sketch below and to keep the reed tongue in the upper position.
Another way to keep the reed and drone bores relatively dry in the first place is to make the device shown and fit it to each drone; it will be found that the reed will remain dry for long periods while the tube and blotting paper will become saturated.
Moisture drops form on the outside and internal surfaces of the tube while some ere absorbed by the blotting paper. This device extends playing time considerably and has no effect on tone or tuning. It also stops the reed from falling into the bag – a problem that seems to afflict some people.
The serious piper will, therefore, take heed the week before, the day before and on the day of the competition, the expected and actual weather conditions and probably save himself considerable grief by being prepared not only for the weather, but for draughty halls and other strange places where pipers are expected to perform and to maintain their instruments in perfect condition.
Another important factor is the judge who keeps one standing for five or ten minutes before deigning to acknowledge one’s presence; such a judge should be prepared to wait an equal length of time so that one can bring one’s pipes back to the condition they were before the interruption, there being roughly three stages in tuning: the initial dry state, the intermediate stage when the instrument is fairly well tuned, and the “final” stage when the drones are given the final touch and remain in tune, steady as a rock, for twenty to thirty minutes or longer, depending on how well the reeds were matched in the first place, which is a separate subject of great importance discussed elsewhere.
* This article was first published in the June 1978 edition of The International Piper.