** As featured in issue 7 **
In the last guitar lesson we looked at formulas for modes in terms of playing solos over changes. This month we’re going to start a series of lessons on expanding our guitar chord vocabulary by using modes in a diatonic context, eventually developing our ideas to include non-diatonic, modal harmony.
So what do we mean by diatonic? In the majority of musical situations we talk about being in a key - for example the key of C major or the key of Eb major. What we’re really referring to here is the idea that pretty much everything in the music is coming from a particular major scale, in other words the seven notes contained within that scale played in many different octaves and positions on the guitar, bass, saxophone, voice or whatever instruments we’re using. If we only use those seven notes then we are said to be using the notes that are diatonic to the key - so diatonic means within a key. If you’ve studied harmony to a reasonable level you’ll already know that the diatonic 7th chords (in fusion and jazz we use 7th’s as our basic chord form) in the key of C major are: - Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7b5.
These basic 7th chords are each numbered using Roman numerals from I to VII giving us the following sequence.
I – Cmaj7
II – Dm7
III – Em7
IV – Fmaj7
V – G7
VI – Am7
VII – Bm7b5
You’ll find these basic 7th chords in the TAB section at the end of the magazine. Many guitar players can play these chords but tend to get a bit more confused when we start to add 9th’s, 11ths and 13ths into the chord, often adding the wrong extensions in and wondering why their chords sound weird. We’re going to learn to use our modal formulas from last month to work out which 9th, 11th and 13th’s we can add into out existing 7th chords to remain diatonic to the key and eventually expand this idea to more complex harmonic ideas. This time we’ll concentrate on 9th chords.
We’re going to associate a particular mode with each chord in the key as follows.
I – Cmaj7 – Major/Ionian – 1 2 3 4 5 6 7
II – Dm7 – Dorian – 1 2 b3 4 5 6 b7
III – Em7 – Phrygian – 1 b2 b3 4 5 b6 b7
IV – Fmaj7 – Lydian – 1 2 3 #4 5 6 7
V – G7 – Mixolydian – 1 2 3 4 5 6 b7
VI – Am7 – Aeolian – 1 2 b3 4 5 b6 b7
VII – Bm7b5 – Locrian – 1 b2 b3 4 b5 b6 b7
Try playing each chord followed by its mode through one octave as outlined in the TAB and you’ll hear how the two fit together so well. The 2nd degree of each scale is the same note as the 9th – if we play through each octave and count the notes we’ll find that the 9th note is the same as the 2nd but up one octave so rather than count up 9 notes we can simply count up 2 and save some time. If we do this for Cmaj7 and use the C Major/Ionian scale our 2nd degree is the note D so we need to add this D into our basic 7th chord. The easiest way to do this would be to take the 3rd back two frets giving us the 9th. This causes a problem in that the 3rd is no longer present in the chord and it’s the 3rd that makes the chord sound major or minor. To solve this problem we’ll rearrange the intervals within the chord and drop the 5th as this note is neutral sounding and dropping it doesn’t affect the tonality of the chord at all. By adding this 9th we get a Cmaj9 chord. When we do this for chord II – Dm7 – we use the Dorian mode and repeat the process from D adding the note E into the chord. The mode associated with each chord is informing us as to which note the 9th is going to be for each chord. Both the III and VII chord’s modes contain a b2 (same as a b9). The b9 interval is the most dissonant sound in music so we avoid playing 9th chords on the III and VII chords and play straight 7ths instead. Once you have this down in the key of C, move on and try it in other keys using the modes to help you figure out the 9ths for each chord.
Any time you have a diatonic chord progression containing 7th chords you can try using these 9th chords in their place. Use your ears as a guide.
You’ll find all the chord voicings and scales from the video in the TAB section at the end of the magazine.
Next time we’ll delve into 11th and 13th chords before expanding into modal harmony and more complex progressions.