Modal Interchange and Minor Keys

Week 7

The plan for today

•Modal interchange•Subdominant minor•Minor Keys•Available tensions – minor keys

Modal interchange•Chords can be borrowed from a parallel tonality for use in the primary tonality. •I.e. Derived from C harmonic minor, used in C major•These are called modal interchange chords

There are many modal interchange chords, but the most common are:

Harmonic Minor IIm7(b5) and V7(b9)

Parallel Natural Minor

Natural minor modal interchange chords:•The natural minor modal interchange chords are:

Subdominant minor

•Natural minor modal interchange chords are either tonic sounds in natural minor, or non-tonic sounds.•Non-tonic minor chords contain the characteristic lowered 6th scale degree of natural minor as chord tones•Tonic minor chords do not contain the lowered 6th as a chord tone

• Identify the b6 scale degree in these natural minor modal interchange chords•Which chords contain the b6?

• Chords without the b6 as a chord tone are tonic minor chords

• Chords with the b6 as a chord tone are non-tonic minor chords

Subdominant Minor

•The b6 scale degree in natural minor can be seen as a b3 of the IV chord in major•This makes the IVm7 chord a subdominant minor•All chords with the b6 are categorized as subdominant minor chords•These chords are the most commonly found examples of modal interchange.

•Examine the example on page 29 of your text•Analyze the progression•Listen to the audio recording

Tonic minor chords

•Im7•♭IIImaj7•Vm7

Non-tonic chords

•IIm7(♭5)•IVm7•♭VImaj7•♭VII7

bVII7 function•The bVII is not a dominant functioning chord•But it can resolve down a perfect fifth to the bIIImaj7 chord•Because the bIIImaj7 chord is not a diatonic chord in the primary major key, the bVII7 cannot be a V7/bIII•It can resolve to any tonic minor chord•See page 30 of your Harmony 2 text

Available Tensions

•The available tensions for modal interchange chords are determined by •either the major key they are played in or:•The parallel key from which they are derived

•Consult pages 31 and 32 of your Harmony 2 text for a breakdown of the available tensions for modal interchange chords.

NOTE:

•Because modal interchange chords are not diatonic to the primary major key, it is very uncommon for them to be preceded by chords that sound like their secondary dominants

Minor Keys

•Minor scales:

•Natural minor•Harmonic minor•Melodic minor•Dorian minor

•Refer to pg 33 of your Harmony 2 Text

•Diatonic functioning chords•Secondary dominants•Extended dominants•Related IIm7 chords•Modal interchange - all occur in minor keys

ACTIVITY:

•Write out each of the four minor scales discussed with a C root note•Build for note chords on each of the scale degrees•See if you can label the chords

Natural minor diatonic chords

Harmonic minor diatonic chords

Melodic minor diatonic chords

Dorian minor diatonic chords

Minor key modal interchange

•There are a multitude of minor key diatonic chords to choose from.•All minor key chords are interchangeable with parallel minor keys. •Refer to page 35 of your Harmony 2 text for a full list of the available chords.

Further observations

•The +maj7 chord from harmonic minor is not diatonic to major•There are dominant structures built on IV, V, and bVII, but only V7 has dominant function.•The Vm7 chord in NOT a dominant chord.•Altered subdominant minor chords bIImaj7 and bVI7 may appear in minor key

Available Tensions

•The same criteria for major key tensions are used to determine minor key tensions. •However, because there are more choices in minor, there are more available tensions in minor.•Also, the 13 is available on minor 7 chords in a minor context if its diatonic and care is exercised.