- A major scale consists of eight adjacent notes, the eighth being the octave
note, and it must have the requisite number of diatonic tones and semitones.
The succession of notes can be divided into two parts, each part called a
tetrachord. The word TETRA means four. A tetrachord is a series of four
notes having a pattern of:
Tetrachord
Whole Tone Whole Tone Semitone
- The four notes of a tetrachord must be in alphabetical order. The example below
is based on the major scale of C. It is visually clear that the two major tetrachords
are separated by one tone.
Note:In all major scales, the semitones occur between the 3rd and 4th notes
and the 7th and 8th.The Major Scale
W W S W W S
Major tetrachord
(Inferior)Tone Minor tetrachord
(Superior)