Circle of Fifths / Music Theory Lesson

Focusing on Fifths

In our previous article, we took a look at the difference between C Major and D Major.

In general, an octave contains 12 different sounds.

This means that there are a total of 12 major keys / major scales
including C major and D major which we previously touched on.

Perhaps you have seen the image below before?

It seems awfully complicated at a first glance.

This Circle of Fifths works as guidelines that
allow you to see the basic sounds you can use in each key.

Lets look at the outer area. The letters on the outer area symbolize M (major) keys.
✴︎ We will take a look at the inner m (minor) later.

First, take a look at info for C and D Major below.

C Major

D Major

As we can see, all 12 major keys are displayed on the circle.
In fact, they are placed in order following a certain rule.

Circle of Fifths

Lets take a look at the number 5 part of the “Circle of Fifths”.

The 5 refers to the 7 half-step interval of the “P5th”.
Pay attention to the clock-wise movement.

On the right of “C” is “G” which is a P5th from C.
On the right of “G” is “D” which is a P5th from G.
A P5th from “D” would be “A”.

The keys change in order of 5ths,
and cycle through all major keys before coming back to the starting key.

What happens when we move counter-clockwise?

On the left of C is F.

You can think of it as a P4th above (5 half-steps up) or a P5th down (7 half-steps down).
It may seem a little confusing but it will be easy to understand on the piano roll.

You can consider it a P4th above (5 half-steps up) or a P5th below (7 half-steps down),
but since we’re focusing on the concept of “5”, we’ll consider it as a P5th down.

Next to F is Bb. This is of course a P5th below as well.
✴︎On DAW it will be displayed as A#

By following this rule you can see each major key
and see what notes are used in each major scale as well.

In addition, there is a rule for which # and ♭ are applied as well.

The note order that #’s are applied goes F, C, G, D, A, E, to B.
Follow this order oppositely to apply ♭’s in order.

This is useful information so be sure to remember this rule!