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** As featured in issue 9 **

For the last two guitar lessons we’ve been looking at expanding our guitar chord vocabulary and understanding by using the modes in diatonic harmony. So far we’ve looked at the formula or intervallic construction of each mode and applied this formula to each chord within a key to produce a series of diatonic 7^th and 9^th chords. For this tutorial we’ll be expanding even further by using these modal formulas to produce diatonic 11^th and 13^th chords in a major key. If you’re new to this idea I recommend you check out the last two lessons and read my column in order to get up to speed.

Before continuing let's remind ourselves of the formula for each mode:

Ionian/Major – 1 2 3 4 5 6 7

Dorian – 1 2 b3 4 5 6 b7

Phrygian – 1 b2 b3 4 5 b6 b7

Lydian – 1 2 3 #4 5 6 7

Mixolydian – 1 2 3 4 5 6 b7

Aeolian – 1 2 b3 4 5 b6 b7

Locrian – 1 b2 b3 4 b5 b6 b7

Remember that we’re assigning a chord to each mode using roman numerals. Let’s take the key of C major giving us:

Chord I – Cmaj7 (Ionian)

Chord II – Dm7 (Dorian)

Chord III – Em7 (Phrygian)

Chord IV – Fmaj7 (Lydian)

Chord V – G7 (Mixolydian)

Chord VI – Am7 (Aeolian)

Chord VII – Bm7b5 (Locrian)

In order to work out the 11^th and 13^th intervals for each chord and add them into the voicing, we need to remember that the 11^th is the same as the 4^th degree of the scale and the 13^th is the same as the 6^th degree.  We’ll deal with the 11^th/4^th first.

The rule for adding an 11^th to a chord is that we usually replace the very neutral sounding 5^th with our 11^th. As the 5^th has very little bearing on the sound of the chord (it simply adds body to the sound) we can remove it and replace it with the much more colourful 11^th. This works for each chord in the key with one exception – the I chord. The 11^th (F) for the Cmaj7 (I chord in the key of C) clashes very badly with the 3^rd (E) of the chord so we don’t play a Cmaj11 chord in the key of C major. We don’t normally play an 11^th chord on Chord I in any major key due to this undesirable clash. You’ll hear me demonstrate this on the video for reference.

Adding in the 11^th to each of the remaining chords gives us the following:

Chord I – Cmaj7

Chord II – Dm11

Chord III – Em11

Chord IV – Fmaj7#11 (the Lydian mode contains a #11 interval)

Chord V – G11

Chord VI – Am11

Chord VII – Bm11 (no 5^th in the voicing so we don’t call it Bm11b5)

You’ll find lots of voicings for these chords in the TAB section at the back of the magazine. Study them and try using them in place of the standard 7^th chords for a prettier sound.

Now onto 13^th chords.

We can play a 13^th chord for every chord in the key without creating any undesirable clashes in the voicings. If the accompanying mode contains a b6 we use the term b13 in the chord symbol. The 13^th is again going to replace the 5^th at the top of the voicing. This gives us the following chords:

Chord I – Cmaj13

Chord II – Dm13

Chord III – Em7b13

Chord IV – Fmaj13

Chord V – G13

Chord VI – Am7b13

Chord VII – Bm7b13

By their nature 13^th chords sound fairly dense and complex and should be used with taste rather than constantly and with a sense of what works for the genre of music you are comping in. Again, you’ll find the voicings in the back of the magazine.

Next issue we’ll be moving on to creating and playing over modal chord progressions using what we’ve learned so far. See you there!