Chord Theory - Altered Dominant Chords
As you work on increasingly complex pieces, you will start running into seventh chords that are altered. Although seemingly more complex, they are simply the seventh chords you have already learned with one or more notes sharped or flatted.
Remember that the dominant seventh chord consists of the root, third and fifth, and adds the flatted seventh from the scale to complete the chord. This can then be altered in several ways. The first is to sharp the fifth, giving us the root, third, sharped fifth and flatted seventh. This can be written several ways, such as C7#5 or C+7. So we have C, E, G# and Bb. Another way of looking at it is that this chord adds a flatted seventh to the diminished triad.
Alternatively you can flat the fifth. This would give us C, E, Gb, and Bb. You will see this written as C7-5. As you can see, you are starting with a diminished triad, then adding the flatted seventh, so this is really nothing new.
Beside the fifth, altered ninths, (the same as the second of the scale up an octave), are also often added. As with the fifths you can sharp or flat the ninth. So C7#9 would be C, E, G, Bb, D#, and C7-9 would be C, E, G, Bb, Db. Once again this is a chord that you already know, in this case C7 with just one extra note added.
You can then combine these as in C7#5-9, (C, E, G#, Bb, Db), C7#5#9, (C, E, G#, Bb, D#), C7-5-9, (C, E, Gb, Bb, Db), and C7-5#9, (C, E, Gb, Bb, D#). The point here is not to overcomplicate these and see them as just variations of chords you already know. Think of this as adding more color to the dominant seventh chord in order to make it resolve even more strongly to the tonic.
Dominant chords are "unsettled chords", needing to resolve to the tonic, and adding these alterations increases that quality. At first, these may not "sound right" to your ear until you get used to these altered harmonies, but in time you will adjust. This is a way of adding tension to your solos and make them much more interesting than just playing the straight dominant chord. In a future article we will go into more depth on this and the scales needed in order to be able to improvise over these chords. For now, practice playing the chords in all twelve keys if you have a chordal instrument. On all instruments, be able to play the arpeggios in all twelve keys. The main thing is to train your ear to hear these altered harmonies. Then you will have even more "paints in your improvisational box".