The Intricacies of Steel Pan Tuning

At the heart of the steel drum musical revolution is the remarkable way in which steel pans are tuned. Rather than just adjust fundamental pitches like most every other major instrument, steel drum tuners achieve the shimmering and buoyant sound of the steel pan by careful tuning of the fundamental plus the harmonic overtone partials (high pitches that sound very lightly as bell like tones above each note). They must do this while maintaining the proper shape, height and tension of a note to very exacting tolerances or the sound quality of that note will suffer dramatically. In a broader sense, the steel pan instrument is being tuned during much of the crafting process, since the principles and some of the tuning techniques are applied at different stages of the process.

Most often, a steel pan is made from a 55 gallon steel drum barrel. The top of the barrel is sunk to create a concave playing surface. It then goes through a series of steps, each of which must be executed in just the right way if the steel pan is to have excellent sound. Some of the main steps and processes are; grooving or engraving the note shapes into the playing surface, backing and the hammering of the metal at various stages to knead, adjust height, acoustically separate and harden specific areas of the note playing surface, cutting the skirt to the proper length for the steel pan instrument being made, firing the steel pan in a fire pit but sometimes with a bunson burner or by baking in a stove, lifting the notes with a wedge to a proper height, rough tuning, applying a finish to the metal and then fine tuning. Tuning is done with a ball peen hammer with a shortened handle. This is just to give you a sense of how steel pans are made. There are many in between steps to this handcrafted process that require specific techniques.

Here, we will give just a small insight into the intricacies of the final tuning process after the steel pan has been crafted. Understanding and developing the ability to hear the harmonic overtone partials that are present in musical notes is essential if a person is going to eventually learn to tune a steel drum instrument. We can use the example of a guitar string to help explain this. When we pluck the string in normal fashion, we hear the fundamental or the main pitch of the note. If we lightly place a finger on the octave or 12th fret and pluck the same string, we hear a pitch with bell like tone and less volume one octave up or twice as high as the fundamental. This is because the 12th fret divides the guitar string exactly in half and makes it easier to hear the octave harmonic overtone that is within the fundamental pitch. If we then place our finger lightly on the 7th fret and pluck, this divides the string into one third and creates a bell like pitch with even less volume that is an interval of a fifth above the octave. In the same way, placing a finger on the 5th fret divides the string in one fourth and creates a very small pitch 2 octaves above the fundamental or twice as high as the fundamental pitch. The next harmonic overtone is an interval of a third and so on.

The harmonic overtones appear in the same order on all instruments including on steel pans. When tuning the Low C note on a lead or tenor steel drum, the tuner will tune at a minimum the fundamental, the octave harmonic overtone and the interval of a fifth harmonic overtone. Although the techniques are many and often sophisticated, anything done to make a steel pan note smaller will raise the fundamental pitch (squeezing the note). Anything done to expand the steel drum note or make it bigger will lower the pitch. The octave harmonic overtone is tuned in its simplest sense by lengthening or shortening the vertical length of the note. The vertical length is an imaginary line starting on the steel drum rim and cutting towards the center of the steel pan playing surface while dividing the Low C note in half. The interval of a fifth harmonic overtone on a lead steel drum is tuned by lengthening and shortening the horizontal length of the note. The horizontal is an imaginary line that runs parallel to the steel drum rim and divides the Low C note in half that way. If you were to draw an “X” through the note, the points at which the X intersects with the edge of the Low C note allow adjustment of the fundamental with the least impact on the pitch of the octave harmonic and also the interval of a fifth harmonic overtone. The steel pan tuner must “trick” the three pitches just mentioned to all be in tune at the same time for a steel drum note to have good sound and be in pitch.

To illustrate the complexities involved in steel drum tuning, just the horizontal has 14 main and distinct points at which pitches can be adjusted. This includes tuning from the underside of the steel pan and tuning “outside the note”, but these 14 points are only a part of the techniques used to adjust the interval of a fifth harmonic. Further, each of the 14 points will simultaneously raise/lower the harmonic and raise/lower the fundamental in various combinations and the tuner must take this into consideration before each adjustment. Metal tension, note height and differing hammering techniques must also be chosen for each tuning hit. Learning steel pan tuning requires a sharp ear and intellect, persistent dedication and years of training by way of demonstration and then practice. Access to enough steel pan instruments is also important. The handbook is free to download as PDF from http://hotpans.se/pan/tuning/pdf/