Basic Music Theory: How to Read, Write, and Understand Written Music

23: Intervals

Major Intervals

All other intervals in a major scale are called major intervals. That leaves

us with seconds, thirds, sixths, and sevenths. The letter used for a major

interval is a capital “M”. These intervals would be written like so:

See example 23.3 below for Major intervals in the key of C major.

It takes two notes to have an interval, so in the example that follows I’ve

put a C below each note, which gives us harmonic intervals up the major

scale. Any of these intervals spread out one after the other would be a

melodic interval.

Example 23.3 Intervals in the key of C Major.

Altering Perfect Intervals

A perfect interval can be raised or lowered, and this changes the quality

of the interval.

A perfect interval lowered a half step becomes a diminished interval.

A perfect interval raised a half step becomes an augmented interval.

Here’s a little diagram to help remember this. The aug is above the P

because an augmented interval is higher than a Perfect interval. The dim

M2 major second

M3 major third

M6 major sixth

M7 major seventh

PU/PP M 2 M 3 P 4 P 5 M 6 M 7 P 8