01.25.07 Music Theory 101: Intervals

The space or distance between notes is called an “interval.” To begin understanding intervals, let’s look at the smallest ones.  The interval between C and C# is a “half step” in size and is called a “minor second.” The interval between C and D is a “whole step” in size and is called a “major second.”

Here is a complete list of interval names, their “size,” and two notes that are that represent this interval’s distance:

MINOR SECOND - HALF STEP - C to C#
MAJOR SECOND - WHOLE STEP - C to D
MINOR THIRD - ONE AND A HALF STEPS - C to E-
MAJOR THIRD - TWO WHOLE STEPS - C to E
PERFECT FOURTH - TWO AND A HALF STEPS - C to F
AUGMENTED FOURTH - THREE WHOLE STEPS - C to F# (also called the “tri-tone")
PERFECT FIFTH - THREE AND HALF STEPS - C to G
MINOR SIXTH - FOUR WHOLE STEPS - C to G#
MAJOR SIXTH - FOUR AND A HALF STEPS - C to A
MINOR SEVENTH - FIVE WHOLE STEPS - C to B-
MAJOR SEVENTH - FIVE AND A HALF STEPS - C to B
OCTAVE or EIGHTH - SIX STEPS - C to C

But this terminology is not consistently used.  Often, half steps are called “semitones” and whole steps are just referred to as two semitones.  This screws up the chart above which then looks like this:

MINOR SECOND - ONE SEMITONE - C to C#
MAJOR SECOND - TWO SEMITONES - C to D
MINOR THIRD - THREE SEMITONES - C to E-
MAJOR THIRD - FOUR SEMITONES - C to E
PERFECT FOURTH - FIVE SEMITONES - C to F
AUGMENTED FOURTH - SIX SEMITONES - C to F# (also called the “tri-tone")
PERFECT FIFTH - SEVEN SEMITONES - C to G
MINOR SIXTH - EIGHT SEMITONES - C to G#
MAJOR SIXTH - NINE SEMITONES - C to A
MINOR SEVENTH - TEN SEMITONES - C to B-
MAJOR SEVENTH - ELEVEN SEMITONES - C to B
OCTAVE or EIGHTH - TWELVE SEMITONES - C to C

Regardless of how you we talk about it - in semitones or half and whole steps, understanding and being able to hear the intervals between notes is crucial to getting any benefit out of music theory as a songwriter - which is my whole point for going through all this here in the first place.

For example, because I can hear two notes in my head and know the interval they represent, I can very quickly - instantaneously - play them.  No hunting for the right note and playing a few bad guesses before landing on the one I want.  Learn to hear the difference between a major third and a minor third, a fourth and a perfect fourth, etc and you’ll be able to get the melodies out of your brain and onto the keyboard or guitar much much faster.

I memorized how the intervals sound by playing them at the piano.  And by listening annoying all my friends by telling them what interval the first two notes of every song were.  Learn them somehow.  You’ll be amazed at how much easier playing by ear and writing becomes.