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Functional tonal harmony
Relating chords by their interval content

Functional means based on functions, tonal means based on tonality, harmony means lively movement through all that emotional space.


So let’s begin with tonality. 99% of the songs you hear day to day are Tonal. Tonality is a system of harmony created & used in the Common-Practice Period (that is, in the Baroque, Classical and Romantic Eras of classical music), so from about 1700 to 1900. Tonal harmony is the ‘standard’ music theory that you learn through your Classical music studies. And, in fact, most of my previous lessons presuppose or function within ‘tonal harmony’.

Tonality has the following features:

  • It uses Major and minor keys
  • It uses a Functional Harmony
  • It has a Tonal Centre (i.e. root note)

So point one is self-explanatory. Points two and three are more interesting. Tonality uses a Functional Harmony and has a Tonal Centre (that is, a Tonic). In tonal harmony every chord has a function, it can be categorised as either:

  • Pre-Dominant;
  • Dominant; or
  • Tonic

The function of a Pre-Dominant chord is to get you to the Dominant chord. The function of a Dominant chord is to get you to the Tonic chord, thus the harmony (that is, the chords) are ‘functional’.

And the Tonic chord is the ‘Tonal Centre’. This can be thought of as a ‘Centre of Gravity’ to which all other chords gravitate and resolved into.

Thus, a tonal chord progression sounds like it is moving towards the tonic. For example, take the below chord progression:

Em7 A7 Dm7 G7 ???

What chord comes next?

We all know instinctively that it should be a CMaj7. It just SOUNDS like it needs to go back home and resolve to the tonic; thus there is a ‘tonal centre’. (Notice also that tonal chord progressions tend to move via the Circle of Fifths).

The G7 gravitates and wants to resolve to CMaj7. This is because all Dominant chords have a tritone interval between their 3rd and 7th (in the case of G7 – B & F). This is known as a ‘diatonic tritone‘. The tritone is a very unstable and dissonant interval that wants to resolve. And it does so either:

  • Inwards to C & E (1 & 3 of CMaj7 – creating a G7 to CMaj7 progression)
  • Outwards to B♭ & G♭ (3 & 1 of G♭Maj7 – creating a D♭7 to G♭Maj7 progression)

This ‘diatonic tritone’ is the basis of all tonal music. It is what makes the Dominant chord feel like it wants to resolve to the tonic (thus making the music ‘tonal’).

Functional Tonal Harmony 1

Part one of three. Discusses consonance and dissonance, construction of the major scale, tendency tones, and harmonic function.

Functional Tonal Harmony 2: Minor mode

Discusses harmony in the minor mode. The three versions of the scale: Natural minor, harmonic minor and Melodic minor, and why we use them.

Functional tonal harmony 3: Secondary dominants

In music theory, a secondary dominant chord is a type of chord that functions as the dominant (V) of a chord other than the tonic (I) chord. This means that it creates a sense of tension that resolves to a chord other than the tonic.

To create a secondary dominant chord, you use the dominant (V) chord of the chord you want to resolve to. For example, let's say we're in the key of C major, and we want to create a secondary dominant chord that resolves to the IV chord (F major). The V chord of F major is C7 (C dominant 7th), so we would play a C7 chord before the F major chord to create a sense of tension and resolution.

The use of secondary dominant chords is a common technique in many musical styles, including jazz, pop, and classical music. They can add interest and complexity to a chord progression by introducing unexpected harmonic changes and creating new tonal centers.

It's important to note that secondary dominant chords should be used tastefully and in moderation, as using them too frequently can create a sense of harmonic instability and disrupt the overall flow of a musical composition.

Harmony is in changes

We build harmony out of different chords as steps of the emotional ladder but what really counts is the movement itself. We can go down and up, slow down or speed up, jump and even fly above if we want to. This is the story the composer tells to the listeners and it's vowen with movements.

The functional relations between chords in a scale can be expanded quite drastically with deeper analysis of underlying intevals, that create the desired change in the mood of the music. Many new relations appear to build up into a huge landscape of the tonal space.

Tonal Harmony in 3D

Functional chords on scale degrees

Here are some common chords that can be constructed for each of the scale degrees in tonal harmony:

Tonic Scale Degrees

  • First scale degree (I): major triad (I), major seventh chord (IMaj7)
  • Third scale degree (iii): minor triad (iii), minor seventh chord (iiim7)
  • Sixth scale degree (vi): minor triad (vi), minor seventh chord (vim7), dominant seventh chord (V7/vi)

Subdominant Scale Degrees

  • Second scale degree (ii): minor triad (ii), minor seventh chord (iim7), dominant seventh chord (V7/ii)
  • Fourth scale degree (IV): major triad (IV), major seventh chord (IVMaj7), dominant seventh chord (V7/IV)

Dominant Scale Degrees

  • Fifth scale degree (V): dominant seventh chord (V7), dominant ninth chord (V9), dominant thirteenth chord (V13), altered dominant chord (V7alt)
  • Seventh scale degree (vii°): diminished triad (vii°), half-diminished seventh chord (viiø7), dominant seventh flat nine chord (V7b9/vii°), fully diminished seventh chord (vii°7)