Musicarta Modes - Mediant Substitution

Mediant Substitution (Part 2)

Mediant substitution is a simple but powerful technique for making all your chord sequences sound more sophisticated. This Module applies the mediant substitution technique to the three riffs in Module Five.

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Here are the three modal minor i-ëVII riffs from Module Five. The left hand column gives the original version. The right-hand column showcases the same three riffs treated with mediant substitution.

  Riff One: Original

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  With mediant substitution

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  Riff Two: Original

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  With mediant substitution

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  Riff Three: Original

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  With mediant substitution

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In this module, you practice the mediant substitution process and experiment with the new sounds you can create from simple two-chord material.

The first riff

Here is the first riff in the table above, original and treated.

  Original

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  With mediant substitution

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Revise the original riff. Here are the right hand i-ëVII inversions used and the chord sequence.

Making the mediant substitution chords

This is how to make the mediant substitute seventh chord for the G minor chords.

You lower the root of the G minor chords a major third (two whole tones, four semitones) to create E flat major seventh chords.

This is how to make the mediant substitute seventh chord for the F chords.

You lower the root of the F chords a minor third (three semitones) to create D minor seventh chords.

The mediant substitution chord sequences

Here is the chord sequence of the riff treated with mediant substitution, shown as slash chords. (There is no change in the first line.)

However, it is not usual to write seventh chords as slash chords. (This is a  Musicarta technique for looking at and learning them.) Here is the chord sequence written out using conventional chord symbols.

Note that we cannot use the circle/square/triangle method to indicate seventh chord inversions.

Use the keyboard diagrams and the chord sequence charts to play the mediant substitution version of the first riff.

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The second riff

  Riff Two: Original

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  With mediant substitution

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Here are the original and treated versions of the second Module Five riff.

The second riff uses chords E minor and D major. Revise the original riff.

Here is the original riff chord sequence.

Here are the mediant substitution chords for E minor and D.

Three possible mediant substitution variations

You, the improviser/composer, choose when and where to use mediant substitution to vary your chord sequences.

Here are three possible mediant substitute versions of the second Module Five riff.

Here is a version with substitutions in the second half of the line.

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You might introduce substitutions earlier in the line and climb back out at the end:

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The extreme is to have substitution all the way through.

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The last chord has been left as D major, but notice how the sequence still wants to cadence into E minor – the mode has got into your head!

Play and listen to the three versions. Think about why and when one version might be preferable to the others. Make your own variation and write it down. You can use slash chords for notation if you prefer.

  Errata. Last line of above audio is Em / Bm7 repeating.

The third riff

The third Module riff 5 uses D minor and C major chords. Here are the original and mediant substitution versions.

  Riff Three: Original

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  With mediant substitution

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Revise the original riff.

Here are the keyboards showing the D minor and C mediant substitution chords you will be using.

The original chord sequence is:

A chord sequence using all the possible mediant substitutions would be:

Listen to the audio of a treated version. Try to hear what substitutions have been made. Make a note – any shorthand will do – and play what you have written down.

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