This episode looks at the theory and practice behind using the mediant substitution, a useful substitution for chord I. Other substitutions such as chord quality and tritone are revisited as a useful way of negotiating a turnaround is explored.

1. The Mediant Substitution
and Other Variations
Podcast #6 - Additional notes
© Copyright Darren Dutson Bromley 2012

2. 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 tonic
D is the supertonic
E is the mediant
F is the subdominant
G is the dominant
A is the submediant
B is the leading note
Where as in the key of Db major:
Db is the tonic
Eb is the supertonic
F is the mediant
Gb is the subdominant
Ab is the dominant
Bb is the submediant
C 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:

3. 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 Am
B D F# is Bm
C E G is C (major)
D F# A is D (major)
E G B is Em
F# 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

4. The chords produced are:
G B D F# is Gma7
A C E G is Am7
B D F# A is Bm7
C E G B is Cma7
D F# A C is D7
E G B D is Em7
F# A C E is F#m7b5
The chord types are consistently the same regardless of the key and look like this:
I
tonic
ii
supertonic
ii
mediant
IV
subdominant
V
dominant
vi
submediant
vii
leading note
Major
Major 7th
Minor
Minor 7th
Minor
Minor 7th
Major
Major 7th
Major
Dominant
7th
Minor
Minor 7th
Diminished
Minor 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:

5. 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 B
Em7 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:

6. 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.

7. 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.

8. 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.

9. 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.