Tag Archives: chromatic scale

chord theory 1: 12 notes

When I started learning music theory, I found it hard work.  Our music system didn’t make much sense to me.  Let’s start with some facts, and maybe the cause of my confusion will reveal itself.  I start with this stuff because if it didn’t make much sense to me, then maybe it isn’t making sense to you or your students.

the 12 notes – with sharps

Note# is the notation for the word sharp, meaning higher in pitch.

A

A#

B

C

C#

D

D#

E

F

F#

G

G#

This is called the chromatic scale.  It has all 12 notes.  The notes get higher from left to right.  A# is a slightly higher note that A, but not as high as B.  Each sharp is higher than the note before it, but not as high as the next note along.  Some notes don’t have an in-between note.  You can see that B and C have no note in between them, and neither do E and F.  This can puzzle people…why do only some notes have in-betweeners?  Its not a question I can answer yet, but it is something you will need to accept to progress in this series, even if I can’t explain why.

the 12 notes – with flats

Note: b is the closest character I can find for the notation for the word flat, meaning lower in pitch.

A

Bb

B

C

Db

D

Eb

E

F

Gb

G

Ab

This is also the chromatic scale.  It has all 12 notes.  Crucially, it is the same scale. Even though some of the notes look different, it is exactly the same.  Where we had sharps – A# is higher than an A, we now have flats – Bb is lower than a B.  A# and Bb are the same note.

sharps and flats

In the sections above, I have given the impression that there are two chromatic scales, that is, it looks like there are two scales of 12 notes.  However, its just one scale, but presented in two different ways, once listing the notes we think of as sharps, and once showing the same notes as flats.

A

A#

B

C

C#

D

D#

E

F

F#

G

G#

A

Bb

B

C

Db

D

Eb

E

F

Gb

G

Ab

A# is the same note as Bb.  C# is the same note as Db, F# is the same note as Gb.

Having made that point, we can now redraw the scale.

A

A# or  Bb

B

C

C# or Db

D

D# or Eb

E

F

F# or Gb

G

G# or Ab

Why do we have two names for A#, and when do I call that note A# or Bb?  Some people may be able to give  you a complicated answer, but for me, if I know the next note is higher than this note, I say I am getting sharper, and if I know the next note that I am playing is lower in pitch, I will say its flatter.

my personal convention

A

  Bb

B

C

C#

D

D#

E

F

F# 

G

G# 

As a self taught guitar player learning from books (before we had the internet), A# was always referred to as Bb.  Don’t ask me why.  For the rest of the series of articles, I will use this convention.  Just remember, sharps and flats are the same thing – its the same note on a keyboard or a fretboard.

intervals, semi-tones and tones

The gap between any two notes is called the interval.   Intervals are measured in semi-tones and tones.  A semi-tone is the next note along, a tone is two notes along.  There is no magic here.

A

semi

Bb

semi

B#

semi

C

semi

C#

semi

D

semi

D#

semi

E

semi

F

semi

F#

semi

G

semi

G#

A

tone

B

tone

C#

tone

D#

tone

F

tone

G

Bb

tone

C

tone

D

tone

E

tone

F#

tone

G#


In this table, which was tremendously difficult to draw, I have shown every semi-tone interval, and every tone interval.  We can use this table to see that the interval from:

  • A to Bb is one semi-tone
  • Bb to B is one semi-tone
  • A to B is a tone (two semi-tones)
  • B to C# is a tone (two semi-tones)
  • D to F# is three semi-tones (or one and  half tones)

12 notes? erm….there are 88 keys on my piano!

circle of notes2

Yup, and on my guitar, there are more than 12 frets.  As students and teachers, we should not take it for granted that a student understands that once you travel from A to G# the notes repeat again, starting from A.   On the keyboard, you can see the notes repeating.  The black keys are the in-betweeners.

88-key-piano-keyboard-layout
Pick any string on this guitar, count 12 semi-tones, and the notes repeat.

guitar fretboard

summary

Whilst this may seem obvious, and this article rather large, we have covered a surprising amount, and there is plenty for a person to be confused about.

  1. there are 12 notes
  2. the notes don’t appear to be named consistently – there are some that are in-between notes, known as sharps or flats
  3. these in-betweeners each have 2 names, but they are the same note
  4. A# is also called Bb, C# is also Db, F# is also Gb, and G# is also Ab (remember the circle)
  5. there is no note between B and C
  6. the interval between B and C is only a semi-tone
  7. there is no note between E and F
  8. the interval between E and F is only a semi-tone
  9. there are two semi-tones in a tone
  10. the chromatic scale is 12 notes long, and the interval between each adjacent note is a semi-tone.  This is the defining feature of the chromatic scale.

Addendum

Since posting this article and moving on to chord theory 2: the C major scale, I have found this lovely diagram which complements my the table above, showing the tones and semi-tones.

keyboard perfect

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