Diatonic And Chromatic Notes
In major and minor keys, the scales we use to make up all the melodies and chords within those keys are called diatonic.
The C major scale is the diatonic scale in the key of C major and the C minor scale is the diatonic scale in the key of C minor.
Diatonic basically means in key and any notes that don’t belong in that scale are called chromatic.
In C major, the diatonic notes are C D E F G A B and the chromatic notes are C#/Db D#/Eb F#/Gb G#/Ab A#/Bb.
The Chromatic Scale
The chromatic scale is a scale made up of every one of the twelve notes from any note to its octave. In other words, it is a 12-note or dodecaphonic scale. You can also see it as a scale made up solely of semitones.
Here is the notation for the chromatic scale starting on three different tonics:
These all use the most common fingering pattern of four notes per string, but this is not always the best method as it involves a lot of jumping and shifting of the hand. Here is the scale again with a more localised fingering:
Visually, this scale resembles a dominant arpeggio, which can help you see how to apply the chromatic scale. Chromatic notes are typical of blues style bass playing and adding these notes to dominant 7 chords can enhance your playing.
Melodic and Harmonic Chromatic Scales
There are actually two types of chromatic scales, although they both share the same notes. The difference is in the spelling of the note names – the harmonic chromatic scale is the same in both ascent and descent and ties in with chordal use.
1 b2 2 b3 3 4 #4 5 b6 6 b7 7
C Db D Eb E F F# G Ab A Bb B
The melodic chromatic scale is different in ascent and descent which is to do with melodic direction. This is actually quite simple – we use sharps when we ascend and we use flats when we descend. So the C melodic minor scale would be:
C C# D D# E F F# G G# A A# B – Ascending
C B Bb A Ab G Gb F E Eb D Db – Descending
This is done to avoid altering the 1 or the 5 as this could get confusing. It also makes it simpler to understand which direction the melody is moving.