In your Jazz career you will hear people talking about altered chords and on your jazz charts you may see G alt. What does this mean? Altered chords are not that hard to grasp, and are an important concept to know about. Any Chord can be altered, but the most common is the dominant chord. For this article we will use dominant 7 chords as the example. In this article you will learn what an altered chord is and how it is made.
The simplest definition of an altered chord is any chord that has chord tones altered. Another way to think of an altered chord is a note in the chord that has been raised or lowered in the scale that correlates to that chord. The notes in a dominant 13 chord are 1, 3, 5, b7, 9, 11, 13. This chord is not altered. When you change one of the chord tones you now have an altered chord. If you take the term “altered” and change it to “changed” or “edited” you will get the idea. This chord is changed or edited to be different from its original form. The changed version of that chord is known as the altered chord.
The more theoretical definition of an altered dominant chord is a chord with a lowered or raised fifth or a lowered or raised 9th. These alterations can be written in different ways. You may see a #11, but this is a b5. You can see a b13, but this is a raised 5th. The 9th and the 5ths are responsible for creating the tensions. Typically tensions are creating on the upper structures of chords. Very rarely do you see anything written or played b2. The difference between a 9th and a 2nd is not the note, but how the note correlates to the root. If there is an octave between the 2 notes it is called a 9th. If it is a whole or half step away from the root it is a second. The octave between the root and the alterations will make the altered note sound better and clash less.
Altered chords which are used a lot in jazz, primarily over the dominant chord are really fun chords. Altered chords are chords that the tones have been changed. The notes that are typically changed in an altered chord are the 5ths and 9ths. You may see these written differently but they 5ths and 9ths are the notes responsible for alterations. Alterations typically appear in the upper structures of chords and are primarily put in dominant chords. Most chords can be altered; however the most common is dominant chords. This makes the dominant chord one of the most interesting chords in music.