3 – Western Music Systems – Scales
A scale is a set of notes (normally seven out of the twelve notes) arranged in terms of increasing frequency (ascending scale) or decreasing frequency (descending scale). For example, C, D, E, F, G, A, B and next C is what is a scale of western music. Note here that seven notes out of twelve have been chosen. That is, these seven notes are chosen from the octave of twelve notes: C, C#, D, D#, E, F, F#, G, G#, A, A#, B, Ċ. In the above scale, the sharp notes have been dropped and only the pure notes are taken into the scale. We know that each note in the octave is separated from the previous and next note by a semitone (half tone). So, between C and C#, the interval is a semitone; the interval between C and D is two semitones or a full tone etc. So, in the above scale (C, D, E, F, G, A, B and next C), the intervals in terms of semitones are 2,2,1,2,2,2,1. Any set of seven notes can be chosen for creating a scale, and different scales have different intervals between each of the seven notes of the scale. But to make sure that the scale notes are spread evenly across the octave, western scales very often call for having two semitone intervals and five full tone intervals, with the semitone intervals being separated by at least two full tone intervals. [This is really an arbitrary convention. You can define a scale of seven notes with intervals of 2,2,2,2,1,2,1 or even 1,1,1,1,1,1,1. The convention of 2,2,1,2,2,2,1 (major scale) is based on having notes in a fashion that is pleasing to the ear]
The scale we saw before, C, D, E, F, G, A, B and next C (denoted as Ċ), which starts with the C note is called the C major scale. Similarly, we can have the D major scale which starts on the note D. The only thing to remember is that for a major scale, the interval differences in the notes should be 2,2,1,2,2,2,1. So the D major scale will be: D, E, F#, G, A, B, C#, Ḋ. The C# major scale will be C#, D#, F(E#), F#, G#, A#, C(B#), Ċ#. Similarly, you can have major scales starting at any of the 12 notes in the octave. The only constraint is that the 2,2,1,2,2,2,1 pattern should be maintained. That is, you can shift one major scale to the left or right on the list of notes to get another major scale. (A note with a dot on top indicates the next octave and a dot below indicates the previous octave). In scales like the ones above, the first note is called the root note (or tonic).
The pattern of intervals of five full tones and two semitones with at least two full tones separating the semitones can be shifted linearly left or right. So, when the interval pattern 2,2,1,2,2,2,1 is shifted to the right we get 2,1,2,2,2,1,2. If we shift once more to the right, we get 1,2,2,2,1,2,2. These different patterns we get when we shift these intervals left or right are called the modes of the scale.
The major scale is a mode of the interval pattern 2,2,1,2,2,2,1. The other modes are given below.
2,2,1,2,2,2,1; – Ionian mode (Major scale), which we saw before
2,1,2,2,2,1,2; – Dorian mode
1,2,2,2,1,2,2; – Phrygian mode
2,2,2,1,2,2,1; – Lydian mode
2,2,1,2,2,1,2; – Mixolydian mode
2,1,2,2,1,2,2; – Aeolian mode (also called the natural minor scale)
1,2,2,1,2,2,2; – Locrian mode
Now, the pattern where the intervals are semitones or full tones is only one of the possible patterns. There can be other scales with seven notes. For example, the so-called harmonic minor scale has the seventh note of the natural minor scale raised by a semitone. So, the intervals look like this 2,1,2,2,1,3,1.
Of course, this pattern 2,1,2,2,1,3,1 can also have seven different modes. But these are not defined, as the very purpose of creating a harmonic minor scale is to change the last interval from 2 semitones to one, so that the leading note (the last note) is close enough to the first note of the next octave so that a longing is created to go to the next note. (This is what a major scale does).
The above scales all had the same note intervals in both the ascending (increasing frequencies) and descending (decreasing frequencies). This needn’t be so. The so-called melodic minor scale (which is another variation of the natural minor scale) has different frequencies for ascending and descending scales. This note also shows four consecutive full note intervals.
So, any set of seven notes can be chosen to form what is called the heptatonic (seven-note scale). The only consideration is that it should produce pleasing melodies and harmonies.
Of course, there is no rule that a scale should be only seven notes. There are some defined scales with only five notes (called pentatonic scales). Similarly, there are hexatonic (six-note) scales, chromatic scales (all 12 notes) etc.
A major scale is supposed to create a happy feeling (it is supposed to be ‘brighter’) but a minor one creates a sad feeling.
The scale is really a menu of available notes for a musician. It is a framework from which to compose a song. Composers can employ any of these notes in the scale in any order (but following the ascending and descending patterns) in a piece of music, but normally a composition uses ascending notes to build tension and then uses descending notes to release the tension to settle down and relax. However, many skilled composers start high and go down. It is left to the composer to create music that is pleasing to the audience. Many musicians occasionally employ notes that are out of the scale (called accidentals) and many singers include slides that go into pitches that are between the notes of the scale (microtones). Music genres like jazz and blues and Indian music singers regularly employ intervals less than a semitone. [The Beatles song Strawberry Fields Forever initially employs a scale that is halfway between A major and B♭ major and later shifts to a scale that is about 15 cents below B♭. There are many such songs. These microtonal scales are obtained by sharp editing and/ or by playing the song at different speeds to raise or lower the pitch. Visit this site.] Of course, keyed instruments (like the piano) are constrained to use the defined notes and have no access to microtones (What we are saying here is that once the piano is tuned, it is constrained to that tuning and cant go to notes in between. But remember that the piano can be tuned to any set of notes including microtones.) It is also important to note that many genres of music employ scales of more than seven notes.
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