Music theory about Intervals

Intervals are the most fundamental part of ear training. All harmonies or melodies can be considered as a collection of intervals. As a beginner you should therefore begin with Intervals and later continue with, for example, Melody dictation to identify a sequence of intervals, or Chord identification to identify harmonies with more than two tones.

An interval is the distance in pitch between two tones. It is labeled by its numerical value and its quality. The numerical value indicates the number of tones of the diatonic scale it includes.

In the staff above, the diatonic tones are shown (i.e. the white keys of the piano) and they are numbered after their position in the C-major scale. C=1, D=2, E=3 etc.

Examples of interval naming: The interval from C (1) to D (2) is a "Second" because it includes two tones, the interval from C (1) to E (3) and the interval from E (3) to G (5) are both a "Third" because they include three diatonic tones.

Quality

The quality can be Perfect, Diminished, Augmented, Major, or Minor.

Unison, fourth, fifth and octave are called perfect intervals. Each of them can be diminished (one chromatic tone smaller) or augmented (one chromatic tone larger). The rest of the intervals within an octave are: second, third, sixth and seventh. Each of them can be major or minor.

Below is an example of a perfect fifth, diminished fifth and augmented fifth and a major and minor third.