Chords and Scales
The defining characteristic of tonal music is the feeling of 'being in key' (as discussed in the Introduction to Tonality). An important factor in creating this feeling is a clearly defined tonic (the note on which the scale starts).
In order for a melody to clearly be in a key, the scale on which it is based needs to have two properties:
- it should be instantly recognisable
- it should be easy to tell quickly which note is the tonic
A major scale, whole-tone scale and a made-up scale starting on C are repeated over two octaves in the example below. Think about how easy or hard it would be to spot that a melody was written using these scales and whether a listener could easily hear the C was the 'tonic'. The table below the example offers some thoughts on these two points.
[If you have time, write a short melody using each of the scales and sing or play it]
(1) a melody written using the whole-tone scale would be very easy to recognise - any four notes produce the very characteristic sound of x.
(2) on the other hand, it is impossible to tell which note of the melody is the tonic (listeners cannot tell the difference between whole-tone scales starting on C, D or any other note).
||(1) the repeated four-note segment (y) creates a recognisable major scale sound.
(2) because y only appears twice and does not overlap, it does not take a very long melody for listeners to be able to hear that C is the tonic.
||(1) the repeated pattern (lower brackets) does not cover the whole scale, and the two five-note groups which do (z1 and z2) are different. This means that there is less of a characteristic sound to this scale compared with the major and whole-tone scales.
(2) the lack of internal similarity means that while the 'tonic' of any short melody using this scale is theoretically easy to find, it would be hard to hear which note is the tonic in practice.
The major scale manages, therefore, to create a distinctive sound whilst making it easy to hear the tonic. It is not the only possible scale to strike this balance, but these properties help explain why this organisation might have come to predominate. Of course, music in the real world rarely sticks to just one scale, but the modulations, chromaticisms and other more complicated features of tonal music still rely on the simplicity of this basic organisation.
Another important consequence of the different arrangements of tones and semitones becomes clear when these scales are transposed. As discussed in the key and modulation section, it is an extremely important feature of tonal music that it can move (or modulate) from one clearly defined key to another.
If you try transposing the major and whole-tone scales so that they begin on c#1 and then d1 you will notice that while the major scale uses a different set of notes in each transposition, the whole-tone scale on D consists of the same notes as that starting on C. In fact, there are only two completely different whole tone scales, whereas there are twelve different major scales. A whole tone system would therefore only have a very limited range of available modulations.
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© Copyright Thomas Pankhurst