Scale is any set of musical notes ordered by fundamental frequency or pitch.
Scale ordered by increasing pitch is an ascending scale, and a scale ordered by decreasing pitch is a descending scale.
The distance between two successive notes in a scale is called a scale step.
For Western music with 12 tones in octave used several definition of steps:
- semitone, half step is 2^(1/12)
- whole step, whole tone, major second is 2^(2/12)
Chromatic scale is a musical scale with twelve pitches, each a semitone above or below another. On a modern piano or other equal-tempered instrument, all the semitones have the same size (100 cents). In other words, the notes of an equal-tempered chromatic scale are equally spaced.
Diatonic scale (or heptatonia prima) is a scale composed of seven distinct pitch classes: 2–2–1–2–2–2–1.
Minor scale: 2-1-2-2-1-2-2.
Pentatonic major scale: 1, 2, 3, 5, 6. Pentatonic minor scale: 1, ♭3, 4, 5, ♭7.
The eight degrees of the diatonic scale are also known by traditional names:
- 1st degree – Tonic (key note)
- 2nd degree – Supertonic
- 3rd degree – Mediant
- 4th degree – Subdominant
- 5th degree – Dominant
- 6th degree – Submediant
- 7th degree – Leading tone
- 8th degree – Tonic (Octave)
The notes of a scale are numbered by their steps from the root of the scale.
- Often, especially in the context of the common practice period, most or all of the melody and harmony of a musical work is built using the notes of a single scale, which can be conveniently represented on a staff with a standard key signature.
- Common-practice harmony is almost always derived from diatonic scales and tends to follow particular chord progressions that have withstood the test of time.