Introduction
The vast majority of music written in the last few centuries has been ‘tonal’. This is the type of music we are all used to hearing day to day. However, in the 1950’s Jazz musicians began feeling restricted by ‘tonality’ and started experimenting with other ways of structuring harmony (i.e. chords).
From Tonality (which encompasses your more traditional Jazz all the way through to Bebop, Hard-bop and Cool Jazz) Jazz musicians moved to Modality (Modal Jazz) and Atonality (Free Jazz – though Free Jazz is NOT necessarily atonal).
In this lesson we’re going to start with the difference between Tonal Harmony vs Modal Harmony.
Just as a semantic aside, when I say ‘modal harmony’ I am referring to the modern meaning of the term – that is Miles Davis/Kind of Blue/Modal Jazz Modal Harmony – and NOT Medieval music or Gregorian Modes.
Tonality
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’).
Modality
Modality has the following features:
- It uses all modes (Ionian, Dorian, Phrygian, etc.)
- It does NOT use a Functional Harmony
- It has a Tonal Centre (i.e. root note)
Modal songs can be written in any mode (not just major and minor), so for example it can be in the key of D Dorian.
In Modal Harmony, chords DO NOT have a function, so in a sense: all chords are equal. A chord DOES NOT need to resolve to any other chord. But there is still a Tonal Centre – for example the note D in the key of D Dorian (i.e. the root note).
But because there is no ‘functional harmony’ the chords DO NOT feel like they need to resolve to the tonic or Dm7 chord. Each chord just floats there by itself as a standalone entity.
In order to achieve this you have to avoid playing the diatonic tritone – because this tritone interval creates a dissonance which sounds like a Dominant Chord and feels like it wants to resolve to the Tonic Chord, thus turning the music tonal.
So it’s a delicate balance. You have to make D sound like the ‘tonal centre’ but you can’t do it by using the function of the diatonic chords. So you:
- CAN’T use a dominant chord to establish the tonic (i.e. A7 to Dm)
- CAN use Pedal point (Repeat Root Note)
- CAN use Ostinato (Repetitive pattern)
Because the majority of music we hear (pop, rock, etc) is tonal and chords are usually built out of stacked 3rds, we’ve learned to associate chords built in thirds with tonal harmony. The way to get around this problem is to build chord with 4ths – that is, use Quartal Chords. By building chords in 4ths, you break that tonal anticipation of the Dominant chord wanting to move to the tonic and you create a more ambiguous, vague and modal sound.
Because modal chords don’t have ‘functions’, they don’t have to go anywhere (i.e. they don’t have to resolve to the tonic). They just float around. So modal songs usually don’t have chord progressions. They just state the key/scale/mode the song is in and it’s your job to play any diatonic chords (i.e. Dm7, Em7, FMaj7, G7, Am7, Bø7, & CMaj7 in the key of D Dorian) and make your own ‘chord progression’.
So then when playing a Modal Song you have to:
- Emphasis the root note in the bass (to reinforce the tonal centre); and
- Avoid playing the diatonic tritone (to avoid tonal sound)
- DO NOT play Bø7
- Play G Triad (instead of G7) to avoid the tritone interval
- Move around the diatonic chords at random but smoothly (generally stepwise)
- Keep the chord movements sparse and simple – not too busy, not too many chords, nice and boring. The chords are there just to create a harmonic underlay.
- Use Quartal Chords (to avoid tonal sound)
Modal harmony creates a more ambiguous and vague sound and is now considered much more ‘modern’ than traditional tonal harmony. Modal Harmony completely changed the way people think about Jazz and improvisation. It gave the soloist greater freedom and choice in his or her solo (I’ll have much more to say about this in the next lesson).
Tonal Harmony vs Modal Harmony Summary
And that, in a nutshell, is the difference between Tonal Harmony vs Modal Harmony. So, in summary:
| Tonality | Modality |
|---|---|
| Uses Major & minor keys | Uses all modes |
| Functional Harmony | No Functional Harmony |
| Tonal Centre (root note) | Tonal Centre |
Have a Listen to
- So What ~ Miles Davis
- Milestones ~ Miles Davis
- My Favorite Things ~ John Coltrane
- Impressions ~ John Coltrane
- Little Sunflower ~ Freddie Hubbard
- Footprints ~ Wayne Shorter