ALTERED CHORDS

An altered (chromatic) chord is a chord that contains at least one altered note in the current key. By altering a chord, a composer can make it sound more colorful or add a tension to the music. 

In the following chapters, the common types of altered chords will be explained. We shall see that some of them have their own symbols, which are used when annotating harmony.

It is important to notice that other altered chords exist which do not fit into any of these common types. In the previous chapters, we saw that certain combinations of scale degrees and chord qualities result in diatonic chords. However, if we use the same scale degrees with other chord qualities, this results in altered chords. For instance, in a major key, the combination of the fifth scale degree and the major triad chord quality results in the major triad chord on the fifth scale degree which is a diatonic chord. However, the combination of the fifth scale degree and the augmented triad chord quality results in the augmented triad chord on the fifth scale degree which is an altered chord because it uses the raised second scale degree. This harmony V+ is relatively often used as a more colorful version of V. The next figure shows a few examples of altered chords that can be used as a more colorful version of V,  V7 and V9.

Figure: Altered chords that can be used instead of V, V7 and V9

Difficulties with altered chords

Sometimes it is difficult to tell whether an altered note is a nonchord tone or it is a part of an altered chord. Nonchord tones were explained in chapter Implied chords, chord tones and nonchord tones and should be ignored during harmony analysis. If we think that the composer used the altered note as an embellishment or for smooth voice leading between chord tones then it is a nonchord tone. If we think that the composer used the altered note to make the chord more colorful then it is probably a part of the altered chord.  

Sometimes, an altered chord can be explained in several different ways. In such a case, the most convincing explanation must be chosen.