Some Very Basic Things to Know About Music Theory

1. Music is organized sound and silence. Sound is energy. Sound is vibration. Sounds are pitches or noises. Humans can hear vibrations from 20-20KHz.
2. The doubling of a vibration (frequency) results in “sameness”. It is called the octave.
3. Within this doubling we divide the sound space into scales. For example:

1. pentatonic scales contain five notes
2. whole-tone scales contain six notes
3. diatonic scales contain seven notes (common usage)
4. chromatic scales contain twelve notes

1. The two diatonic scales in common usage in Western music since around 1600 are “major” and “minor.” Their differences can be demonstrated by calculating the sequence of whole steps (W) and half steps (H) starting from the tonic (note #1):

a. major W W H W W W H

b. minor (natural) W H W W H W W

5. Thus, the intervals (distance) from the tonic to the other tones are:

Major: Maj2 Maj3 P4 P5 Maj6 Maj7

Minor: Maj2 Min3 P4 P5 Min6 Min7

1. The names of the scale steps are:

1. tonic (the tonal center or home pitch)
2. supertonic (above the tonic)
3. mediant (half way between the tonic and the dominant)
4. subdominant (a P5 below the tonic)
5. dominant (vibrates 1.5 times faster than tonic)
6. submediant (half way between the tonic and the subdominant)
7. leading-tone (it pushes up to the tonic by
8. half-step motion)

1. Three tones may be combined simultaneously to form a triad (basic harmonic unit):

Major triad: root Maj3 P5​
Minor triad: root Min3 P5​
Diminished triad: root Min3 dim5​
Augmented triad: root Maj3 aug5

The functional name of a triad is derived from the name of its root. Its number is, likewise, derived from the scale step number of the root and is written in Roman numerals. Triads may be inverted and/or rearranged (that is, the root does not always have to be the bottom note and the third, the middle and the fifth, the top). The most important triads are the tonic (I), the subdominant (IV), and the dominant (V). Chords can be increased in size by the addition of 7ths, 9ths, 11ths, and 13ths. Chromatic harmony uses chords from outside the scale.

1. A melody is a characteristic sequence of pitches (a mix of chord tones andnon-harmonic tones) and rhythms. Melodies contain phrases that end with cadences.