Understanding key signatures: minor keys

In our second music theory lesson, we explore the minor Circle of 5ths; learn the unique relationship between a Major scale and its relative minor scale; learn how to build each minor scale by examining its key signature and position on the circle; and learn how the different minor scale scales are related.

Goals:

  • Understand the difference between minor and Major scales
  • Understand the relationship between minor and Major scales on the circle of 5ths
  • Understand how to build minor scales using the Circle of 5ths

What You Need To Know:

  • Every Major key has a corresponding minor key, called the relative minor, or natural minor
  • A Major key shares a common key signature with its relative minor key
  • Relative minor: The same group of notes as Major, but starting a minor third below
  • Minor third = 4 half steps (or 2 whole steps)

Example: Finding the relative minor of C Major

1) Start on C
2) Go down a minor 3rd to A
3) Play the same notes as C Major but finish on A instead of C

Comparing the relative Major and minor scales visually:

C Major looks like this: C-D-E-F-G-A-B-C
A minor looks like this: A-B-C-D-E-F-G-A

Two octaves, C Major on top of A minor –> same scale starting on different notes:

… A B C D E F G A B C D E F G A B C … (C Major)
A B C D E F G A B C D E F G A B C … (A Minor)

Viewing the Major and minor scales numerically (as scale degrees), C Major on top of A minor:

… 6 7 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 … (C Major)
1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 2 3 … (A Minor)

Notice:

  • The A minor scale starts on the 6th degree of the C Major scale, and the C Major scale starts on the 3rd degree of the A minor scale.

Comparing minor and major keys using the circle of 5ths (minor keys inside, lowercase with a dash; Major keys outside, uppercase):

Interpreting the Major/minor Circle of 5ths:

  • minor key letters rotated a quarter turn clockwise (90 degrees to the right) around the inside of the circle from Major key letters. But…
  • some keys not the same in Major as in Minor
    • G#, D#, A# in minor, not in Major
    • Db, Gb, Cb in Major, not in minor
  • In minor, Eb/D# minor are the halfway points around the circle from A; Eb has 6 flats, and D# has 6 sharps.

Table of minor key signatures:

Using the Circle of 4ths/5ths to build minor scales:

Building minor scales around the circle uses the same process as building Major scales, but the scale degrees you raise or lower are different in minor.

1) Start with A minor: A-B-C-D-E-F-G-A (all white keys)
2) Number the notes 1-8 starting on A (with 8 being the octave, same as 1
3a) flat or lower the 2nd (B to Bb) when you move clockwise to D minor, or
3b) sharp or raise the 6th (F to F#) when you move counterclockwise to E minor.

Building D minor from A minor
Building E minor from A minor

Moving farther clockwise around the circle, D minor to G minor:

1) keep the flat you already have (Bb)
2) lower the 2nd of D minor, E to Eb
3) move the tonic to G

Building G minor from D minor

G minor has both Bb and Eb as well as C-D-F-G-A on the white keys.

Moving farther counterclockwise around the circle, E minor to B minor:

1) keep the sharp you already have (F#)
2) raise the 6th of E minor, C to C#
3) move the tonic to B

Building B minor from E minor

B minor has both F# and C# as well as D-E-G-A-B on the white keys.

Moving backwards around the circle:

  • Counterclockwise, flat key to flat key –> act like you’re adding a sharp

1) raise the 6th
2) move the tonic down a Perfect 4th (or up a Perfect 5th)
3) remove a flat from the key signature

  • Clockwise, sharp key to sharp key –> act like you’re adding a flat:

1) lower the 2nd
2) move the tonic up a Perfect 4th (or down a Perfect 5th)
3) remove a sharp from the key signature

Notice:

  • Major and minor key signatures are in the same order around the circle, with the flats and sharps in the same positions
  • you raise and lower the same notes in minor that you did in Major – only the number values, or degrees, have changed

Major: lower the 7th for flat keys; raise the 4th for sharp keys
minor: lower the 2nd for flat keys; raise the 6th for sharp keys

But you’re still lowering B to Bb when you go from no flats to one flat, and you’re still raising F to F# when you go from no sharps to one sharp.

Using the circle, understand the relationships between the note you add to the key signature to get to the next key, and the original key that you’re altering:

Moving clockwise: Add the note 5 steps clockwise from the original tonic (4 steps from the tonic to which you’re moving) – e.g., moving from A to D, replace B with Bb.
Moving counterclockwise: Add the note 3 steps counterclockwise from the original tonic (2 steps from the tonic to which you’re moving) – e.g., moving from A to E, replace F with F#

IMPORTANT:

  • remember enharmonic spellings – e.g. the note you add to G# minor to get D# minor is written E#, but it’s F on the Circle (because E# is not a key)
  • Be consistent with your sharps and flats: flat keys contain only flats and sharp keys contain only sharps.

Return to Top | Return to Blog Index