So far in this Jazz series, we have learned all the forms of root position seventh chords from the major and minor keys. We have also learned to play each Major and minor triad in different Major/Minor Keys. The subject of Part 3 of this Jazz series are what are called "altered" or "dominant" chords.
First of all,
ALTERED CHORD-A chord with one or more of its members replaced by a either a non-chord tone (NCT) from that scale or by a tone that might not be part of the scale.
So we can therefore lump all altered chords the following 2 categories...
-Altered chords with NCT(s)
-Altered chords with tones from outside the key that are plugged in.
Since this is a Jazz series, it is worth noting that in Jazz lingo, altered chord simply refers to any dominant where either the chords 5th or its 9th has been altered from what it would normally be.
In a similar fashion to how simple triads are comprised of Roots,3rds, & 5ths, altered chords are comprised of Roots, 3rds, b/#5ths,b7ths, and b/#9ths.
The normal places where one encounters "altered chords" are in places where they are substituting in for a dominant chord (ie V/Vii)
Here are some of the most commonly occurring "altered chords"
SUSPENDED CHORDS-These are just your basic triad where-in the 3rd has been replaced by either a 2nd or a 4th. Either way, they will have a tendency towards resolution where the 2nd or the 4th resolves by step to the 3rd they initially replaced. (In a sus2 chord the 2nd clashes w/ the root. And in the sus4 chord, the 4th clashes w/ the 5th of the chord.)
Augmented Chords-These are simply basic triads where the 5th has been bumped up a 1/2 step to an augmented 5th (aka minor6th). The normal resolution for these chords is for the augmented 5th resolve down by step to a perfect 5th. (The dissonance in these chords is caused by the clashing btw/ the 3rd and the augmented 5th)
This concludes part 3 of this series...Be sure to experiment with different types of "altered chords" and have fun (-: