Chord Theory 6: Omitting Notes
So far we’ve learned about the basic chord types (major, minor, diminished and augmented), and taken a cursory look at each of the possible sixth, seventh, 69, and extended chords that can be developed on top of these basic triads. However guitarists only have four fingers and six strings to play with, while these chords have as many as 7 notes. Its not realistic (or always musical) to play every note in these complex chords. Instead, we can omit notes which aren’t considered to be important to the sound of the chord.
Omitting the Fifth
Usually one of the most unessential notes of any chord is the fifth. In these chords the fifth is essentially “inert”. It does not contribute to the sense of major or minor, nor does it add any interest (tension, dissonance or sense of forward movement) to the sound. Therefore it can typically be omitted quite safely without affecting the stability or tonality of the chord.
As an example, while a Cmaj7 would normally have the notes C, E, G and B, it is common to leave the G out, keeping only the C, E, and B. This is also true for dominant and minor type chords.
Of course, with chords which have a b5 or #5 (such as augmented and diminished type chords), it would normally be best to try to keep the fifth as these altered fifths do play an important role in the sound of the chord (they add dissonance and forward movement).
Omitting the Root
Omitting the root is also a possibility, though this is not nearly as straight forward as omitting the fifth. Like the fifth, the root is essentially inert and does not contribute any interest to the sound of the chord. The root does however, dictate the tonality of the chord and as such, we must exercise caution when employing rootless voicings.
For example, omitting the root from a Cmaj7 chord (C, E, G, B) would leave us with the notes E, G and B, which is the same as an E minor triad. We need a strong sense of harmonic context to prevent rootless voicings from sounding ambiguous or taking on the character of another chord. The following guidelines should help you in developing good taste when using rootless voicings.
- When playing in a band with a bass player or major harmonic instrument (such as piano), you will have more luck using rootless voicings since the other instruments will provide harmonic context, ensuring that the chord does not sound ambiguous
- If you are the only harmonic accompaniment rootless voicings will work better used part way through the duration of the chord. For example, two bars of Cmaj7 could possibly be changed to a bar of Cmaj and a bar of Emin. The initial bar of Cmaj will clearly provide the actual harmony and the Emin, will then simply sound more like a ‘passing chord’ and not take away from the intended harmony
- It is safer to omit either the root or the fifth. Omiting them both in the same voicing can sound very unstable. If you omit the root, try to keep in the fifth and vice versa
These guidelines are particularly important when creating rootless major or minor chords. Rootless dominant chords on the other hand can be used much more freely.
Rootless Dominant Seventh Chords
Unlike maj7 and min7 chords, dominant chords contain an interval known as a tritone. This interval is more or less unique to dominant chords, making it possible to fully imply dominant harmony with only two notes – the third and seventh in the chord. This means that the only ‘essential’ notes in a dominant chord are the third and the seventh, and that both the root and the fifth can be omitted freely without causing any tonal instability or harmonic ambiguity.
Being able to freely omit the root and the fifth gives us room to add in more harmonically interesting notes such as ninths and thirteenths. For instance rather than playing an unadorned C7 chord we could play a more interesting C13 (C, E, G, Bb, D, A). As it is incredibly difficult to play all of these notes together as a chord, we can instead omit the root and fifth (C and G) keeping only the other, harmonically more interesting notes – E, Bb, D and A.
Omitting Other Notes
Of course, we are not limited to omitting the root or the fifth. We are also able to omit tensions (such as the ninth or thirteenth) if necessary for practical reasons (such as fingering), or for musical reasons (such as needing a leaner voicing or barer harmonic texture). For instance, a Cmaj13th chord can have the ninth freely omitted, or, conversely the thirteenth could be omited and the ninth kept (which would effectively result in us playing a Cmaj9th chord).
Similarly it is sometimes desirable to omit the 7th from a major type chord (reasons for this will be discussed in a future post). So in the case of a Cmaj13th chord we may choose to omit the seventh, but keeping both the ninth and the thirteenth (effectively resulting in a C69 chord).