- Definition of a Scale
A Scale is known as series of notes that can be played successively in both ascending or descend order. It forms the basis of melody. Diatonic scale for instance, usually spans an octave. There is no melody that doesn’t have its scale. There are many kinds of scale, but in this article, diatonic scale is considered.
- Kinds of Scale
In Western and other world’s cultures, there are six kinds of scale. These are tritonic scale (a scale of three notes), tetratonic scale (a scale of four notes), pentatonic scale (scale of five notes), hexatonic scale (scale of six notes), heptatonic scale (scale of seven notes) and Diatonic Scale (scale of eight notes)
Diatonic scale is a kind of scale that is made up of both tones and semitones. A semitone (also known as half step) is the smallest distance between two notes. For example: C-C#, B-Bb, E-F, B-C, and so forth.
Tone, on the other hand consists of two semitones. It is also known as a whole step. For example: C-D, E-F#, B-C#, D-E and, so forth.
In the major diatonic the semitones are found between the 3rd and 4th, 7th and 8th degrees. In minor diatonic (natural minor), the semitones are found between the 2nd and 3rd, 5th and 6th degrees.
- Building a Scale
Diatonic scale has five tones and two semitones. Hence, a major diatonic scale can be constructed using the below formula: T T St T T T St. T= tone, St= semitone. The above is the shape of a major diatonic scale. From the above, C major scale will be: C D E F G A B C1
A minor diatonic scale can be built using the below formula: T St T T St T T. T= tone, St= semitone. The above is the shape of a major diatonic scale. From the above, A minor scale will be: A B C D E F G A1
A minor and C major are closely related. The relative minor of C major is A minor. The relative major of A minor is C major. These two keys have the same key signature (no flat, no sharp).
There are three forms of minor diatonic scale. These are: the natural minor, harmonic minor and the melodic minor. The natural minor is 100% diatonic. Harmonic and melodic, there is at least one interval that is more than a tone.
In the harmonic minor, the 7th degree is raised while ascending or descending. Therefore, A harmonic minor is A B C D E F G# A1. In the melodic minor, the 6th and the 7th degrees are raised while ascending and restored or naturalized while descending. Therefore, A melodic minor In ascending order is A B C D E F# G# A1, and A1 G F E D C B A in descending order.
Note that the 6th degree of a major scale is the first degree of its relative minor scale. The 3rd degree of a minor scale is the first degree of it relative major scale. Major scale and its relative minor share the same key signature.
- Scale Degree Names
Each degree of the diatonic scale has a name that relates to its function. Thus, the major diatonic scale and all the three forms of the minor share these terms. Each degree as well as the triads built on it has its function especially when dealing with harmony (harmonic progression).
|1st||Tonic||The tonal center – the final resolution tone.|
|3nd||Supertonic||One step above the tonic.|
|3rd||Mediant||Midway between the tonic and dominant|
|4th||subdominant||The lower dominant – the 5th tone down from the tonic (also the 4th tone up from the tonic. Next important to the dominant.|
|5th||dominant||So called because its function is next important to the tonic|
|6th||Submediant||The lower median – Halfway between tonic and lower dominant (subdominant). The third tone down from the tonic. (Also the 6th tone up from the tonic.|
|The 7th tone up from the tonic (also a 2nd tone down from the upper tonic). It has a strong relationship with the tonic. It often leads melodically to the tonic.|
|8th||Upper tonic/ octave||An octave higher from the tonic. The 8th tone up from the tonic. It’s the upper tonic center. The upper final resolution tone.|
For more, read The Concept of Leading Tone and Subtonic, What Is the Leading Tone of Ab Harmonic Minor Scale? Tonal Harmony: Learning Principles/Prerequisites, The Concept of Triad, The Concept of Seventh Chord, The Characteristics and Resolutions of Secondary Dominant Chords, Augmented Sixth Chords, Neapolitan 6th Chord.