Practical Chord Theory

So far we have dealt only with the mapping out of the fretboard and now we are going to start looking at applying the knowledge we have worked on. I would recommend that you re-read the last Chapter directly after finishing this one to make sure that all the principles covered so far are clear and fully understood.

Each section from now on will relate back to the first two chapters and by linking them together we shall be able to make our own chord inversions, create our own arpeggios and begin to look at improvising in a more logical way.

Firstly we must set out the formulas for all the chord types using intervals to denote a chord's construction.

Chord TypeAbbreviationFormula
Maj I III V
Maj7 maj7 I III V VII
dom7 7 I III V bVII
Aug + I III #V
Min - I bIII V
Min7 -7 I bIII V bVII
dim ° I bIII bV
min7b5 -7b5 I bIII bV bVII
sus4 sus4 I IV V
sus2 sus2 I II V
add9 add9 I III V IX

These are the basic chord forms that we can work from. You will notice all chords that have 'dom' before the number are of a major tonality and have a III and a bVII. The dominant chord family must be treated with care because although the VIIth will always be lowered , any other interval above that will not be altered unless stated in the name of the chord; e.g., G9 will contain the I, III ,V bVII (dom 7 formula) plus the IXth. In the case of G7b9, the 9th would be lowered by one semi-tone. This is also the case for the 11th and 13th intervals where the chord is again built upon the dom7 formula and the extra intervals are added without being altered unless specified in the chord name.

Note Note: In classical music theory all the intervals beneath the highest number would also be included in the chord i.e., a G13 would also contain the 9th and 11th. This is impractical for the guitar since we are limited to the amount of fingers and strings we can use to form the chord.

The same rules apply to every chord regardless of tonality; i.e., Gmin9 will contain a bVII but will also contain the 9th. Gmin7b13 will contain the bVII but would also contain the 9th and the 11th.

Altered chords are dominant chords that have both the 5th and the upper register intervals raised or lowered. These chords are formed exactly as their name implies so that G7#5b9 will be made of a G7 chord with the 5th raised one semi-tone and the 9th lowered one semi-tone. Altered chords play a huge role in jazz styles because of their voice leading potential.

Played on their own they will sound strange and unresolved due to the altered tension that is created within the chord. To get a good idea of how these chords are used, try looking for any sheet music by Duke Ellington. His use of altered chords in composition is breathtaking and would be the best reference you could have for these applications.

Copyright Dale Churchett © 1995. All Rights Reserved.