The tuning of traditional musical instruments like string, brass and wind instruments is fairly straightforward you tune the note to the right pitch and it will automatically sound right. The tuning of steel pans is much more complicated, since the pitch and the timbre - the "colour" of the sound - have to be adjusted independently. This means that the tuner has to control both the fundamental, constituting the playing pitch, and the upper partials (harmonics), producing the timbre, while he is doing the tuning. If the upper partials are not in a harmonic relationship to the fundamental the note will sound harsh and metal-like. See the theory section for more on tone generation and a discussion of partials.
The tuning process can be seen as composed of three main steps:
- Coarse tuning - the metal of the notes is softened and the notes are put at the right pitch before the fine tuning starts.
- Fine tuning - adjustments of pitch and timbre while the pan is hanging in its playing position.
- Blending - final tuning after the surface has been finished.
The prime instrument for tuning is your ear a good sensibility in pitch discrimination is needed to become a competent tuner. An electronic tuning device can be used as an aid for judging the pitch, but when it comes to harmonics, only your ears (or rather, your brain) will do the job.
The tuner alternately taps the notes with a small hammer and a rubber-tipped tuning stick to hear the sound of the note during the tuning. The fundamental - the pitch of the note (the one written in the score) - can usually be heard while hitting the note with the hammer, but as you begin to focus on the upper harmonics you will need the stick.
Fig. 9.1 Tuner Lawrence Mayers at work.
The type of hammer that is used for the tuning depends on the size of the notes. The following recommendations can be used as a guide for your personal choice: Notes with a length more than 15 cm - a fairly heavy hammer (2 kg) with a large, rounded head. Notes 8-15 cm - a light (less than 1 kg) hammer with a plastic head (usually the same as the smoothing hammer). Notes smaller than 8 cm - an ordinary hammer with a rounded head. See appendix B for further measures on these hammers.
The reason for using the different hammers is the following: A heavy hammer is needed to produce enough force to tune the larger notes. A hammer with a plastic head will make fewer marks in the metal on the medium sized notes. For the smallest notes a metal head is needed to get enough impact and precision in the positioning of the strokes.
The tuning stick may be a regular playing stick, but often it is better to use a stick that is a bit heavier and harder than the ordinary playing stick. The extra weight can be used to decide if the note is "stable" by hitting it hard and see if the pitch stays the same or changes. If the tuning stick is hard, i.e., has less rubber, it is easier to hear the harmonics - the partials - of the note.
The tuner holds the stick in his left hand and the hammer in his right hand and hits the note alternating with the hammer and the stick, see fig. 9.2. One stroke with the hammer is usually followed by two or three hits with the stick to hear the timbre of the sound clearly.
Fig. 9.2 Using hammer and stick to tune.
The stand used to put the pan on while doing the softening and the coarse tuning has to be designed so the pan can rest on its skirt, leaving the note surface free to vibrate in the middle. This is usually accomplished by using a padded wooden box with the same side length as the diameter of the pan, see fig. 9.3. The box can be mounted on a stand so you can tune standing up, or you can put it on the ground to tune sitting down, see fig 9.1. A temporary tuning stand may also be made out of the leftover part of the drum, putting a truck tyre on top of it to rest the pan on while tuning, see fig 9.4.
Fig. 9.3 Professional tuning stand.
It is also practical to have a tuned steel pan or another instrument at hand to "calibrate" your ear at the right pitch of the note you are tuning. A tuning device will be of less use at this stage, because it will be unable to detect the pitch of the harsh-sounding tone. Your ears are probably better at doing this.
Fig. 9.4 Temporary tuning stand made from the left-over part of the drum and a car tyre.
To raise the outer notes while doing the softening before tuning, the tuner generally uses a bent iron (like a specially made crowbar), see appendix B. A new tool that is getting more common for raising the outer notes nowadays is specially shaped wooden wedges. See fig. 9.6 and section II for more about this development.
General steps in tuning
The first, coarse tuning of each note may be seen as consisting of several different steps, but they are interlinked with each other, so when you see a tuner working it can be hard to realise what he is doing. The result of the first part of the tuning should be an independent-sounding note with a definite pitch and a steel pan-like timbre. The steps towards this are: softening of the metal, tuning of fundamental and octave tuning (adjustment of timbre).
The softening of a note and the tuning of the pitch is actually done at the same time. While the tuner softens the note he listens to the pitch and tries to get the metal adequately stretched. When the metal is soft enough and he starts to concentrate on the pitch, he also involves the third step of the tuning. This is where he listens to the timbre of the note and adjusts the octave at the same time as he is positioning the pitch. This continuous flow of work is good to keep in mind while reading the step-wise description of the tuning below.
As a rule of thumb, the tuning of a pan should start with the process that affects the metal the most and has the greatest impact on the sound. You then successively move towards finer adjustments. The reason for this is that the stretching of the metal during the tuning will affect surrounding notes as well as the one you are working on. There is no sense in doing fine tuning on one note if you are going to soften and coarse tune the note next to it later.
If a note seems impossible to tune, leave it at the closest pitch you can get and go back to it when you have worked around the pan. The tensions in the metal might be in a more favourable condition then. As you will get tired listening to the banging and concentrating on the pitch, a pause is also recommended when things seem to get impossible.
Sometimes during the tuning, the tuner may decide to listen to another note to "calibrate" his ear. This other note can be either a note with the same pitch in an already tuned pan or a tuned note in another octave of the pan to be tuned.
As the stretching of the metal when tuning one note is affecting the already tuned ones, the tuning has to be done in a circular manner, working round the pan several times. While tuning the outer notes, the inner ones will be affected, so you have to repeat the procedure again, tuning the inner notes and then the outer ones, until everyone is in pitch. A good rule of thumb for this circular tuning is to "take the worst sounding note and try to make it the best".
Softening the metal
The softening is the first part of the tuning and it is done by hitting the note up and down several times. The softening effect is included in the tuning of the pitch. You are softening the dent while you are hitting it up and tuning it while you are lowering it again, listening to its sound and pitch.
The purpose of the softening is to "loosen up" each note and give it a tone that is fairly independent of the surrounding notes. The tempering has made the metal of the note areas stiff. This is the desired effect to some extent, but the notes should not be as stiff as the surface between them. To enable the notes to sound independently, the metal in the dents and the "joint" at the grooves has to be made softer. This is accomplished by flattening the notes and the restoring them several times. The surface of a note usually has to be hammered up and down again 5-6 times. For the easier notes, such as the inner ones, a couple of times will usually be enough. But some other notes may have to go up and down 10-20 times before they are sounding well.
Fig. 9.5 Raising an outer note with a "crowbar" iron. Note the cutlass blade held against the side of the drum as protection.
It is important that the notes get softened over their whole surface, otherwise proper tuning will be impossible. On the smaller inner notes this is usually no problem, but on the bigger outer notes you have to start working at one end and then go over the whole surface. The first time an outer note is raised, the hammer is used on the innermost part (the part nearest to the inner border) of the note. The second time it is raised in its middle, as well as the inner part. The following times you raise the surface closer to the rim each time, but you also make the inner parts come up together with it. A schematic procedure for the raising of outer notes is suggested in fig. 9.6.
When working close to the rim, it can be hard to reach with the hammer and its head may be too big to raise the note properly. The tuner often uses a crowbar-like, bent iron for this work, see fig. 9.5 and appendix B. If the top of the iron is sharp, a blade of a cutlass is held between the tip of the iron and the skirt to protect it from getting marks. A wooden wedge can be also used to raise the outermost parts of the notes. The wedge is put resting against the skirt and hammered upon, see fig. 9.6.
Fig. 9.6 Alternative methods to raise outer notes for softening.
Each time a note is raised, it is lowered again while listening to the pitch, see "Tuning the pitch" below. The first couple of times a note is lowered, you may flatten it out fully to get it softened faster, but as it starts to sound better you usually leave it convex. For each tuning round, the surface is raised a bit higher. Don't try to do all of the raising at once, because it can easily be to much. It is better to have to do the softening some extra times than to risk to get the metal too slack. It is important to listen to the pitch while raising the note. The pitch should not rise more than about half an octave above the intended final pitch.
The softening is complete when the note seems to have a tone that is relatively independent from its surroundings. It should be easy to hear the pitch and the timbre should be steel pan-like. You may also use your hand to feel when the note is soft enough it should be "springy", without "buckling" (flapping over to the other side).
Tuning the pitch
When you start the tuning of the fundamental, you concentrate mainly on the pitch to get it low enough. The sound of a note with few upper harmonics is rather dull, so in the beginning it might be quite hard to hear its exact pitch.
The coarse tuning always starts by raising the note and then lowering it, while listening to the pitch, until it reaches its right frequency (or a bit below that). This usually has to be done several times to get the dent softened and the note low enough, see the description below.
The main steps in the procedure for softening and coarse tuning can be concluded in the following list:
1. Hit around the note, on the groove, from above. This is done to "set" the note - to define the working area. It also strains the metal in the note and insures that the groove is flat.
2. Raise the note by hitting it from underneath, see softening. While this is done, you can hear the fundamental of the note first getting lower, then starting to rise. The note should usually be raised a bit beyond the point where the pitch started to rise.
3. Lower the note, and thus the pitch, by hitting it from above in the middle region. Try to get the fundamental down to the intended pitch or a bit below it. If the pitch starts to rise before it has come down to the right level, the metal in the note is not "slack" enough. Then hit down the dent a bit beyond the point where it started to rise and start over again from point two, this time raising the note a bit more to stretch the metal further.
The process of raising and lowering the note often has to be repeated a number of times before the metal gets slack enough to produce an independent-sounding tone. In a good note, the tone usually comes out after two or three times, but some notes have to be raised ten times or even more.
During the first, softening part of the tuning, the precise pitch of the fundamental is not so important - it is more crucial that the note gets a sound of its own.
When the tuner lowers a note, he gets an indication of how much it needs to be raised the next time. He adjusts the amount of raising to stretch the metal enough to produce a better tone the next time it is lowered. If no partials are heard while a note is lowered, then it probably needs to be stretched further. If, on the other hand, it is raised too far, the metal will get too slack when lowered and the note will lose its sound, thus making it unusable. It is better to stretch the note too little and repeat the process several times, than to risk stretching it too much the first time.
Sometimes during the tuning the note may lose all of its tension and give away a very low tone without overtones. This might be cured by hitting on the groove from above to increase the tension or by raising the note and starting again with the lowering.
When the note has been softened and has a sound of its own, the fundamental is adjusted by changing the "resonant" size and the height of the dent. Larger dent - lower pitch. Higher dent - higher pitch. To understand this, one must keep in mind that the size of the sounding dent is defined by the shape of the metal surface inside the groove rather than by the boundaries set by the groove. The sounding dent is always a bit smaller than the area delimited by the groove.
Fig. 9.7 Tuning the fundamental. Overview and cross-section of note.
There are some rules of thumb for the tuning of the fundamental, see fig 9.7 for an explanation:
- Hitting from above in the middle region lowers the pitch.
- Hitting from underneath in the middle region raises the pitch.
- Hitting from above near the side of the dent raises the pitch (because the dent gets smaller).
- Hitting from underneath near the side lowers the pitch (the dent gets bigger).
- Hitting on the groove from above stretches the metal, and thus raises the pitch. (Don't hit on the groove from underneath - this might ruin the shape of the note.)
The rules listed above are general, but due to small differences in shape and differing conditions in the metal, each note has its own characteristics and has to be treated in its own way. Sometimes a stroke can have an effect opposite to the intended because of irregularities in the note arch. When lowering the dent, the tuner adjusts the arch towards its final, correct form. The problem is to know exactly which shape this is for each note.
When some notes have been tuned, they may start to interfere with each other. This is usually good, but sometimes the sound of a note can disturb the tuning of another one. In this case, it is necessary to damp notes nearby to hear the harmonics properly.
First, the tuner checks which note is the disturbing one by damping the notes, one at a time, with a finger while hitting the note to be tuned. If the interference disappears when damping a particular note, this is the one causing the trouble. This note may be damped more permanently by pasting something on to the note surface. A sheet of a heavy material stuck on to the note may be used for this purpose. This can be a note template with a sticky backside or a piece of a magnetic plastic sticker for refrigerators or cars. The tuner can also decide to remove the sound of an interfering note totally by hitting it flat to be able to concentrate better on a note that is hard to tune.
It can be seen as a rule of thumb that, if a note is hard to tune, always check surrounding notes to see if they interfering with the note you are working on. If so, damp them before continuing. All pans seem to have at least one note that tunes easily and catches energy from the vibrations in other notes - the tuners call that one "the leading note".
At this first stage, just coarse-tune each note to something near the right pitch, before you start to soften the next one. During the first part of the tuning the note can be left at a pitch that is a bit too low, because it usually raises when the other notes are being tuned.
Tuning of overtones (partials)
In this part of the tuning, the timbre of the steel pan tone is adjusted. This is done by tuning the overtones (or partials, as the acousticans call them) of the note, and it has to be done completely by ear. The partials are the parts of the sound that form the special steel pan timbre, the characteristic that makes it possible to recognize the sound as coming from a steel pan. When the octave and the higher overtones are brought into the tone, harmonics will be added to the tone and give it a longer, more pure sound. The partials are generated by vibrations along and across the note and are tuned near the ends of the notes. For a more general description of partials, see the theory section.
The partial tuning is actually done at the same time as the final adjustment of the fundamental. This is because it is hard to hear the pitch of a note if it not is sounding good, i.e., has a proper octave.
Before starting the tuning of partials you need to know that the note dents all are elliptical in physical shape. The ideal proportion between length and width of the note seems to be somewhere near 5 to 4 (but it works with other proportions too). The inner notes are nearly always oriented with the length axis of the ellipse pointing towards the centre. In the outer note circle, on the other hand, the notes are usually oriented with the length axis along the rim.
The octave partial of the note is generated by a vibration along the elliptical note. This vibration is adjusted by hitting the note from above in the end regions, see fig. 9.8. When this is done, the vibrating dent will get smaller and the fundamental will rise, together with the octave. The fundamental is then lowered by hitting in the middle and the procedure of adjusting the octave in the end is repeated. If the pitch of the fundamental starts to rise before the octave has reached its right pitch, hit the note down fully and then up and start over again. This may sound easy and straightforward, but it is in practice the most complicated part of steel pan tuning. You might say that this is the key to good tuning.
Fig. 9.8 Tuning the octave. Note seen from above.
A crucial thing in octave tuning is to get the partials to act and sound well together. The tuners call this to "marry" the fundamental and the octave. This means that the fundamental and the octave have an harmonic relationship to each other. The octave should have a frequency that is exactly twice the fundamental.
The thing that is hardest to understand in tuning is how to move the octave without moving the fundamental and vice versa. A good tuner actually moves them at the same time, but in a way that will make them marry at the right pitch.
The upper partials are adjusted by changing the arch of the dent, rather than its size and height as in pitch tuning. To understand the tuning of partials you need to know how they sound and how their modes of vibration are distributed across the note. So, before you begin the tuning of the partials, take a look at the text and the pictures in the chapter on tone generation in the theory section.
The next higher partial, the third, is generated by a vibration across the note and is tuned along the side of the note. The relation of this partial to the fundamental forms part of the timbre, but it is not at all as important as the octave. In good pans, this partial is tuned to a harmonic interval in relation to the fundamental. Most ideally this interval would be a fifth above the octave, but often it is tuned to a third or fourth above it. This is because the fifth cannot always be reached with the fundamental at its right pitch. It is important that the interval to the fundamental not is disharmonic, such as a musical second or less, because this will make the note sound false and harsh.
A good trick to hear the octave and the third partial better is to generate a "flageolet". This is done by putting a finger in the middle of the note to damp the fundamental and then hitting the note near the end with the backside of the stick. See the chapter on tone generation in the theory section for an explanation of how this works.
Tuning of inner notes
The tuning usually begins with the inner notes in the middle region of the pan. These are the easiest to tune, and their sound will help with the tuning of the outer notes, which usually is much harder. Each note is treated according to the general steps described above softening, pitch tuning and octave tuning. The steps are integrated with each other, so when you see a tuner working, it will all look like a single process. First the note is raised, then the pitch is lowered by hitting from above in the middle region, then the octave is adjusted by hitting from above in the end region of the note.
Fig. 9.9 Method for the tuning of inner notes.
The tuner often reserves one end of the elliptical note for adjustments of the octave. This is usually the outermost end of the inner note, but if a note is hard to tune, the tuner may decide to shift the octave adjustments over to the inner end to see if this works better. An overview of the tuning regions for the inner notes can be seen in fig. 9.9, together with a cross-section of the note. Please note that the height of the dent in the figure is exaggerated. As seen from fig. 9.9, the final shape of the note dent is asymmetric within the note region, the dent being a little lower at one end.
If an inner note responds in a peculiar way, this might be because it has a badly shaped groove. This may be corrected by hitting around the note to bring it back in shape again. Especially important is the small region between the inner and the outer notes of an octave pair.
Tuning of outer notes
When all the inner notes have got their right pitches and a crude timbre, it is time to tune the outer notes. The softening, pitch tuning and timbre adjustment of the outer notes is done in the same way as for the inner ones, but with some special tricks.
Begin by hitting around the note on the groove. While doing this, some strokes on the rim may be beneficial. This will stretch the metal in the note and make the dent come up easier. The next thing to do is to raise the note. While raising an outer note, especially on the tenors, the lack of space near the skirt that will make it difficult to hit with the hammer. Therefore a bent iron rod, shaped like a crowbar, or a wooden wedge is used to do this, see fig. 9.6.
The note is lowered by hitting it from above with the tuning hammer. On the larger notes it is important to distribute the strokes even over the middle part, and not hit in the same place several times. See fig. 9.10 for a definition of the middle working area. If a note bulges down and turns concave when you lower it, you are probably hitting it too much in the middle (or maybe the note has not been backed enough). If so, raise it once again and try to hit it in a wider area around the centre. Raising a bulging note can sometimes be done by hitting at the rim to stretch the metal.
Fig. 9.10 Regions for the tuning of lengthwise oriented outer notes. Valid for all pans except tenors.
If a note is bulging so much that it seems impossible to tune, there is a trick to re-shape the dent. The tuners call this to "tighten" the note. Hold the palm of your hand on it to keep it still while you re-shape it. This is done by hitting around your hand and it will result in a smaller, more sturdy dent.
When studying the tuning of the octave in an outer note, one has to keep in mind that the outer notes are oriented with their length axis in different ways in different pans, see fig. 9.11. In all pans except the tenors, the lengths of the outer notes are tangential, i.e., the length axis is oriented in parallel with the rim. On the tenors, the outer notes are rotated 90 degrees, i.e., with the length axis radial, pointing towards the middle of the pan.
Fig. 9.11 Orientation of outer notes in different pan types.
As the most important partial, the octave, is acting lengthwise the procedures for its adjustment must be different for these different categories of pans. In most pans the end regions of the elliptical note will be reserved for octave tuning. See fig. 9.10 for an overview of the effects and regions for octave tuning in regular outer notes. For the tenors, the tuner usually reserves the inner end of the outer note for adjustments of the octave, see fig. 9.12.
Start the octave tuning of the outer notes with a note that has a tuned corresponding inner octave note. It will be easier to hear the sound of the octave of this one. On larger notes, check that the octave vibrations at both ends of the note have the same pitch. The best way to check the octaves is to hit the note with the hard backside of the stick.
Fig. 9.12 Regions for the tuning of outer notes on tenors.
When an outer note is beginning to sound good, the tuner lifts the pan from the tuning stand to check that the pitch stays the same and the timbre is still good. This is done because the tuning stand damps the vibrations of the skirt and this often affects the tone of the outer notes.
If a big outer note not have an evenly shaped arch, a special problem may occur: The pitch of the octave may be different in the two ends of the note. The best way to check this is to damp the note with a finger in the middle and hit it with the hard end of the stick at each end of the note.
While tuning the outer notes, a new problem will arise. The formerly tuned inner notes will start to act together with the partials of the lower note. This is all well as long as the note is sounding together with its octave counterpart, but might be a problem if it acts together with some other note. This may be handled by damping the note as described above in the section for general steps in tuning.
Octave pair tuning
The process of octave pair tuning means that the tuner adjusts the notes in octave pairs to make them sound well together. This is often done to some extent while tuning the outer notes, by adjusting the corresponding inner one at the same time. But it can also be done as a separate step when all the notes of the pan have got their own sound.
During the later part of the tuning of the outer notes, it is very important that their inner octave counterparts have the correct pitch, otherwise it will be impossible to tune the octave of the outer note. This is because the fundamental of the inner note will interact with the octave of the outer note. A mistuned inner note may "pull" the octave of the outer note off from the right pitch and confuse the tuning. You may also end up with two notes that have pitches very close to each other (within a few Hertz). This will result in unpleasant, fast "beatings" and the sound of the note will be harsh.
The octave pair tuning starts by tuning the inner octave note. After that, the octave of the outer note is tuned and the fundamental is adjusted together with it. The tuner repeats this around the pan and "goes by octaves", adjusting each inner - outer note pair together.
Fig. 9.13 Tuning of octave pairs.
At this stage it is also good to do a final check that the notes "have their own tone". This is done by damping the corresponding octave to see if the note still sounds good. Sometimes you may find that a note is "living" totally on its octave counterpart. This means that it has a quite different sound and pitch without the octave note. Try to avoid this situation by giving the note a new start with softening and coarse tuning again. Softening and coarse tuning at this late stage will affect the surrounding notes in an unfavourable way, so the sooner these "dead" notes are spotted the better.
A pan with many octave notes, such as a tenor or a double tenor, is harder to tune than a guitar or a bass, due to the interaction between the many notes. But it is easier to get a good timbre in a multi-octave pan if the notes in the upper octave support the lower ones with higher partials. This is the reason why the higher pans have a more brilliant sound than the lower ones.
The octave pair tuning is the last thing done while the pan is resting on the tuning stand, and it may be considered as the last step of the coarse tuning.