DIATONIC AND ALTERED TONES

Each key divides all note names into diatonic tones and altered tones. Diatonic tones are considered native to the key while altered tones are considered foreign to the key. Altered tones are also called chromatic tones. They are called chromatic because they add variety to music or, so to speak, they add new colors to music (Greek word “chroma” means “color”). They are called altered since they are created by altering diatonic tones.

Diatonic tones of a major key can be found as the note names in the major scale with the same tonic. For instance, we can find the diatonic tones of the C major key as the note names in the C major scale. Thus, the diatonic tones of the C major key are: C, D, E, F, G, A and B. The altered tones of the C major key are all the other note names. 

Figure: The diatonic tones of the C major key can be found as the note names in the C major scale

Diatonic tones of a minor key can be found as the note names in the melodic minor scale with the same tonic. For instance, we can find the diatonic tones of the C minor key as the note names in the C melodic minor scale. Both the ascending and descending sixth and seventh scale degrees must be included. Thus, the diatonic tones of the C minor key are: C, D, Eb, F, G, Ab, A, Bb and B. The altered tones of the C minor key are all the other note names. 

Figure: The diatonic tones of the C minor key can be found as the note names in the C melodic minor scale