An interval is the pitch relationship between two tones. You may think of them as the space or distance between two tones. When working with intervals, it is beneficial to visualize them using the staff. Intervals are named by the number of notes with different letter names that can be held within them. They may be measured harmonically(vertically) or melodically(horizontally).
Naming Intervals
There are two parts to naming intervals: the quality and the number. You may use even or odd numbers 1-8 to number intervals. Intervals may have the quality of Major, Minor, or Perfect.
Interval Numbers
Odd-numbered intervals will always be a line to a line or a space to a space on the music staff. Even-numbered intervals will always be a space to a line or a line to a space on the staff.
Perfect, Major, and Minor
Intervals including the tonic, the fourth, and the fifth scale degrees of a major scale are known as perfect intervals. The unison and octave scale degrees are also perfect intervals.
Intervals including the tonic ascending upward to the second, the third, and to the seventh scale degree of a major scale are major intervals.
Minor intervals are created by making a major interval one half step smaller. This can be done by raising the bottom note or lowering the top note.
Augmented and Diminished intervals
An augmented interval is created by making a perfect or major interval one half step larger (without changing the interval number).
A diminished interval is made by making a perfect or minor interval one half step smaller (without changing the interval number).
Enharmonic Intervals
Enharmonic intervals are intervals that have the same sound but are written differently.
Inverted Intervals
You may invert an interval by making the lower tone the higher tone and vice versa.
Compound Intervals and Simple Intervals
Simple intervals are contained within one octave. Compound intervals are greater than an octave.
Melodic and Harmonic
A melodic interval is one in which the two tones are positioned beside each other and sound one after the other.
Harmonic intervals are ones in which the two tones are stacked on top of each other and sounded simultaneously(together).