Episode 6 : The Mediant Substitution and Other Variations

The Mediant Substitution and Other VariationsPodcast #6 - Additional notes

© Copyright Darren Dutson Bromley 2012

The Mediant Substitution and Other Variations.

To understand the term mediant substitution we first need to look at the degrees of a major scale.

Each scale can be given a name:

1st 2nd 3rd 4th 5th 6th 7th

Tonic Supertonic Mediant Subdominant Dominant Submediant Leading note

These are general names which refer to the position of the note, regardless of the key or the notes name.

Here is a C major scale: C D E F G A B C

C is the tonicD is the supertonicE is the mediantF is the subdominantG is the dominantA is the submediantB is the leading note

Where as in the key of Db major:

Db is the tonicEb is the supertonicF is the mediantGb is the subdominantAb is the dominantBb is the submediantC is the leading note

Chord Construction.

Chords are created by harmonising each degree of the scale with a note a 3rd above and a note a 5th above to produce a triad and a 3rd, 5th and 7th to produce a 7th chord.

Taking G major as an example.

The notes of a G major scale are:

From the note G, the note a 3rd above is B and the note a 5th above is D. From the next note in the scale which is A, the note a 3rd above is C and the note a 5th above is E.

If we repeat the process with the whole scale we arrive at:

G A B C D E F#

G B D A C E B D F# C E G D F# A E G B F# A C

These are the triads which are diatonic to the key of G major and they can be given chord names:

G B D is G (major)A C E is AmB D F# is BmC E G is C (major)D F# A is D (major)E G B is EmF# A C is F# diminished

These triads form the basis for many of the chords played on the guitar, regardless of the position or the amount of strings played. G major for example only consists of the notes G B and D.

We could also add a 7th to each of these triads:

G A B C D E F#

G B D F# A C E G B D F# A C E G B D F# A C E G B D F# A C E

The chords produced are:

G B D F# is Gma7A C E G is Am7B D F# A is Bm7C E G B is Cma7D F# A C is D7E G B D is Em7F# A C E is F#m7b5

The chord types are consistently the same regardless of the key and look like this:

Itonic

iisupertonic

iimediant

IVsubdominant

Vdominant

visubmediant

viileading note

MajorMajor 7th

MinorMinor 7th

MinorMinor 7th

MajorMajor 7th

MajorDominant 7th

MinorMinor 7th

DiminishedMinor 7th b5

The Mediant Substitution.

A particularly effective chord substitution is replacing chord I in a progression with chord chord iii, the chord built on the mediant. This is known as a mediant substitution and is effective in breaking the predictability of chord I by adding a more unexpected chord change.

In the key of C major, chord iii, the chord built on the 3rd note of a C major scale is Em or Em7. Chord iii is always a minor chord. This can be used as a substitute chord for chord I, Cma7.

The progression could be played as:

Em7 has similar qualities to Cma7, mainly due to the fact they share many of the same notes.

Cma7 contains the notes C E G BEm7 contains the notes E G B D

The notes E G and B are common to both chords.

Looking at a I vi ii V progression in the key of Eb we would have:

We can employ a mediant chord substitution to chord I, the Ebma7.

Here is an Eb major scale:

The third note of an Eb major scale is G, which when harmonised give the chord Gm7. The progression using this substitution would look like this:

Applying Chord Substitutions.

Taking the last part of the standard Misty as an example. Here it is as a chord/melody arrangement.

This is then followed by the turnaround of Ebma7 Cm7 Fm7 and Bb7 or in this case Bb13.

Using a mediant substitution it is possible to substitute Gm7 in place of Ebma7. (G is the 3rd of the Ebma7 chord) We’d now have the following sequence.

Chord Quality Substitutions.

Chord quality substitutions were discussed in a previous episode and is where it is possible to change the ‘gender’ of a chord, minor can become major, major 7th could become dominant 7th etc.

We can employ chord quality substitutions to our progression to make it more interesting. By turning the m7 chords to dominant7th chords, the chords have a stronger resolve onto each other whilst maintaining the ‘harmonic intention’ of the original progression.

The progression could now become:

The Tritone Substitution.

We discussed this substitution in depth in a previous episode so it would be worth reviewing it if it seems a little unclear. It is possible to substitute a dominant 7th chord built on the flattened 5th of another dominant 7th chord.

For example C7:

Taking a C major scale. From the root note of C it is possible to go up a perfect 5th.

C D E F G A B C

and flattening it giving the note Gb.

This is the root note of the chord we can use as a substitution for C7, in this case Gb7.

We could apply this to our progression giving us:

It is possible to make the progression sound smoother by adding a few extensions and alterations to the chords. By sharpening the 5th of Gb7 it is possible to keep the note D on top.

It would be possible to change Fm7 to F7 by using another chord quality substitution. It could then be played as F13 so as to maintain the D top note. This would then be followed by Bb13.

The whole turnaround could be played like this:

Try using this turnaround in different songs, you will probably have to transpose it into different keys. Also try applying these techniques to other songs and progressions, they are useful and can create some interesting sounds.

See you next time.