In music, a scale is a sequence of musical notes in ascending and descending order that provides material for or is used to conveniently represent part or all of a musical work including melody and/or harmony. Scales are ordered in pitch or pitch class, with their ordering providing a measure of musical distance. Scales are divided, based on the intervals between the notes they contain, into categories including diatonic, major, minor, and others, with a specific group of notes thus being described as a C-major scale, D-minor scale, etc.
Scales, steps and intervals
Scales are typically listed from low to high. Most scales are octave-repeating; meaning their pattern of notes is the same in every octave. An octave-repeating scale can be represented as a circular arrangement of pitch classes, ordered by increasing (or decreasing) pitch class. For instance, the increasing C major scale is C-D-E-F-G-A-B-[C], with the bracket indicating that the last note is an octave higher than the first note, and the decreasing C major scale is C-B-A-G-F-E-D-[C], with the bracket indicating an octave lower than the first note in the scale.
The distance between two successive notes in a scale is called a scale step.
The notes of a scale are numbered by their steps from the root of the scale. For example, in a C major scale the first note is C, the second D, and the third E and so on. Two notes can also be numbered in relation to each other: C and E create an interval of a third (in this case a major third); D and F also create third (in this case a minor third).
Types of scale
Scales may be described according to the intervals they contain:
- for example: diatonic, chromatic, whole tone
Or by the number of different pitch classes they contain:
- Very common: pentatonic, hexatonic, heptatonic scales, having five, six, and seven tones respectively.
- Used in prehistoric and rarely on contemporary folk music: diatonic or two, tritonic or three, tetratonic or four
- Used in jazz and modern classical music: octatonic or eight.
