Chapter nine - Take me home

When stacked together into triads, the same melodic tendencies still exist giving the chords tendencies.  A chord containing unstable tones sets an expectation for those tones to be resolved.  Their melodic resolutions are in another triad in the key.  Thus we can build a sense of drive with the chords, employing this to move away from the key note (build expectations) and back towards it (satisfy expectations), helping to establish the key note as the centre of this activity.  We take a look at how to construct chord progressions employing these tendencies to bring home the sense of music being built around the scale's key note.  We'll do the same for other scales in later chapters.  If needed, I suggest a quick review of the summary of the previous chapter on melodic tendencies in the major scale.

 

Learning outcome

When major scale notes are stacked into triads, the individual note tendencies still exhibit themselves, thus giving a palette of chords of varying stability.  Triads with several unstable tones of the key create greater expectations for those tones to be resolved by the following chord.  We can employ these tendencies both to control listener's expectations, and to bring out the sense of the key.   We'll look at the common progressions of the major scale triads that achieve this.  Again, the idea is to immediately or eventually satisfy or break these expectations.  Progressions whose root notes (not necessarily the bass note) move in fourths or fifths create a lot of drive, as a consequence of the way successive chords gain or lose unstable tones after the move.  For example, the progression I maj, IV maj, I maj, V maj, I maj is extremely effective. 

Imagine a crowded noisy bar, and you're in conversation.  You manage to extract this thread of sound from all the noise going on, with everything else becoming background to be ignored.  Similarly, the lowest note and highest note of a chord stand out (assuming similar volumes for all the chord notes).  If either or both the outer notes of a triad's voicing are unstable in the key, this gives even more drive, creating stronger expectations.

 

Triads and stability

A listener has expectations that an unstable tone will move (resolve) next to a neighbouring stable scale tone, if chords are present or not.  When we build triads with the major scale, any unstable tones in the triad each sets its own expectations to be resolved (to another triad containing the tone(s) of resolution).  So this lets us create chord progressions that meet expectations, delay these, or ignore them.

Unsurprisingly, the amount of instability present in a major scale triad depends on the number of unstable major scale tones present in that triad, and how unstable they are.  We can form three groups of triads, according to how much drive (expectation) they create for replacement.  We'll examine chord progressions in the next section to see how we can utilise this drive.   Here we'll learn the three groups (stable, medium drive, high drive).

We'll now look at the triads, overlaid on top of our note tendency diagram.  Our first group of triads Imaj, III- and VI-,  are deemed stable.   III- and VI- have two stable notes in common with Imaj.  As a result, they can also act as variants of Imaj.  In this group Imaj is the most stable, then VI-, then III-.

chapt6-1-tendency.png chapt6-6-tendency.png                                                        chapt6-3-tendency.png

Our second group of triads, the IVmaj and II- chords, have medium drive.  IVmaj contains two unstable tones, and II- contains three unstable tones.  Both of these contain the second most unstable tone in major,  4.  II- is more unstable than IVmaj.  Both are more unstable than the stable group of triads.

chapt6-4-tendency.pngchapt6-2-tendency.png

Looking at the tendency arrows,  it's clear that the I chord is expected to follow a medium drive chord.  For example, in the ii chord, 2 creates an expectation of 1, 4 expects 3, and 6 expects 5.  

The VI- chord, having two notes in common with IV maj, can be used as a medium drive chord (in which case, it has the weakest drive in this group).   When used like this, it is often followed by a high drive chord to build further tension.  When used as a stable chord, it would be used as a resting chord at the end of a phrase and its underlying chord sequence.

The job of a medium drive chord is to make the listener expect that a stable chord is following next, but that expectation is not very strong.  However, we can create even more expectation by moving from a medium drive chord to even more unstable territory, found in the third group of chords, the high drive group.  These contain the most unstable major tone, 7.

The triads Vmaj and VIIo have high drive.   Vmaj is less stable than any of the second group.  VIIo is even more unstable.  Visually, we can see that both chords are pulling strongly (the 7 and the 2) to the 1.

chapt6-5-tendency.png chapt6-7-tendency.png

 

The III- chord has two tones in common with the Vmaj chord, and when used with its 3rd (which is the 5 of the key) in the bass, it can act as a weak high drive chord.  When used like this, it is followed by a stable chord, if we want to satisfy expectations.  When used as a stable chord, it would be used as a resting chord at the end of a phrase and its underlying chord sequence.

 

Common root progressions

From above, we see there is a hierarchy amongst the triads, in terms of their drive.  Here these are summarised, ordered by stability.  The most unstable is at the top.

High Drive

VIIo

Vmaj

(III-  with 5 of key in bass, when followed by stable)

Medium Drive

II-

IVmaj

(VI-  when followed by stable)

Stable

III-
VI-

Imaj

 

The expectation is for a medium drive or high drive triad to be followed by a stable triad.   Therefore moving in the opposite direction increases drive. i.e. from stable to medium, or stable to high drive.

One of the simplest, yet massively used, progressions, is just repeating Imaj  IVmaj, and eventually ending on Imaj.  The IVmaj follows expectations back to Imaj, and Imaj moves to IVmaj, away from stability to create the expectation again.  A common way of moving between chords is to use voicings that retain any common notes, and to minimise the moves between changing notes.  In the following examples, duplicate the root of the triad in the bass (left hand on piano, or on bass guitar say).   Play the suggested voicings with right hand on piano, or on guitar.  Remember Imaj is shorthand for I<1, 3, 5>.

Try playing Imaj followed by IV <1, 3, 5d>.   In terms of key locations, the note I is retained, while III moves to IV, and V moves to VI. 

Compare this to Imaj followed by IVmaj

Similarly, repeating   Imaj  IVmaj  (eventually ending on Imaj) is very common. 

Vmaj sets up a much greater expectation to move to Imaj.  The V of the key is frequently retained in the move.

E.g.  Try I <3, 5, 1u> followed by V <5d, 1, 3>

Compare this to  Imaj followed by V <3d, 5d, 1>

Other variations on this theme include Imaj, IVmaj, Vmaj, Imaj  and Imaj, IVmaj, Imaj, IVmaj, again extremely common.

Imaj, III-, IVmaj ...    I<5, 1u, 3u>, III<b3, 5, 1u>, VI<1, b3>

Imaj, VI-, IVmaj, Vmaj has yielded countless tunes.


 

Summary

Any major scale unstable tones in the triad each sets its own expectations to be resolved (to another triad containing the tone(s) of resolution).  So this lets us create chord progressions that meet expectations, delay these, or ignore them.  We found there is a hierarchy amongst the triads, in terms of their drive.  Here these are summarised, ordered by stability.  The most unstable is at the top.

High Drive

VIIo

Vmaj

(III-  with 5 of key in bass, when followed by stable)

Medium Drive

II-

IVmaj

(VI-  when followed by stable)

Stable

III-
VI-

Imaj

 

The expectation is for a medium drive or high drive triad to be followed by a stable triad.   Therefore moving in the opposite direction increases drive. i.e. from stable to medium, or stable to high drive.