Modern Jazz – Tonal vs Modal Harmony

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Hi guys, So, I thought I’d make a series of lessons about Modern Jazz Theory. Now Modern Jazz Theory can be described as the gradual rejection and reshaping of traditional music theory. So, in these videos I’m going to go through how Jazz moved away from your more traditional music theory towards more exotic and avant-garde music theory. So, essentially, how Jazz moved from Tonality, which is the more traditional Jazz, into Modality, which is Modal Jazz, and then all the way through into atonality, which is more your Free Jazz. And just as a pedantic aside, Free Jazz is not necessarily atonal, but rather this is just a broad generalization of a general trend of Jazz moving away from tonality into atonality, as it moves towards Free Jazz. But I’ll have more to say on that in future lessons. So, we’re going to start at the start in this lesson, and I’m going to try to explain the difference between tonality or tonal harmony and modality or modal harmony.

Now i should also clarify that when i say ‘modal harmony’ I’m referring to the modern meaning of ‘modal harmony’. That is not Medieval music, not Gregorian modes, or the church modes, or anything like that. But rather the Miles Davis, John Coltrane, Modal Jazz sense of the word of ‘modal harmony’. Now tonality is a system of harmony created and used in the Common Practice Period. That is, in the Baroque, Classical and Romantic ears of Classical Music, so from about 1700 – 1900. And tonal harmony is the sort of standard music theory that you learns through your classical music studies. And, in fact, most of my videos presuppose or function within a tonal harmony framework. Now tonality has the following features: It generally uses major or minor keys; it has a functional harmony; and it has a tonal centre, that is, it has a root note.

So the first one is easy. So, tonal music is generally written in a major or a minor key. So either in C major or some kind of C minor, say, like C natural minor or C harmonic minor. Now the second and third points are that tonality use a functional harmony and has a tonal centre, again, that is, a root note or a tonic chord. Now, I have a separate video where i go over the diatonic function of chords in a bit of depth, so you can go check that out if you like. But essentially in tonal harmony, every single chord has a function and is placed in a kind of hierarchy with the tonic at the top.

So if, for example, we take the key of C major and we look at all of the chords in the key of C major. We have the chords C major 7, D minor 7, E minus 7, F major 7, G7, A minor 7, and and B half diminished. Now each one of those chords in the key of C major can be prescribed to one of three different functions: either predominant, dominant, or tonic. So, the 2 and the 4 chord have a predominant function, which essentially means they create a little bit of tension. The 5 and the 7 chord have a dominant function, which essentially means they create a lot of tension. And the 1, 3 and 6 chords have a tonic function, which essentially means they have no tension whatsoever and are used to resolve the tension from the other chords. So, really then, the function of a predominant cord is to get you to a dominant chord. And the function of a dominant chord is to get you to a tonic chord.

Thus the term ‘functional harmony’. And in fact that’s why a 2-5-1 chord progression is such a strong sounding chord progression. Because, essentially, you’re going from a predominant, to a dominant, to a tonic functioning chord. And so the tonic chord, that is, the C major 7, is the tonal centre, and it can be thought of as a kind of ‘center of gravity’ to which all the other chords gravitate and resolve into. So, that is, in tonal music, which has a functional harmony and a tonal centre, we have a chord progressions that sound like they’re moving somewhere. They sound like they’re moving towards the tonic. So if, for example, I play the following chord progression [music] and I stop there.

Now, sing the chord that comes next, sing the chord that’s next in the progression. [music] Right, we all instinctively know that the next chord should be C major 7. It just sounds like that chord progression needs to go back home and resolve back to the tonic. Resolve back to that C major 7 chord. Resolved back to the tonal centre. So the chord G7 gravitates towards C Major and wants to resolve into C Major. Now, this is because all dominant chords have a tritone interval between their third and their seventh. So, in the case of G7, we have the notes B and F which creates a tritone interval. Now, a tritone is very unstable and is a very dissonant interval and because it’s so unstable it wants to resolve inwards to the C and the E, which is the 1 and the 3 of the C Major chord. So, yeah, Right, so that’s effectively a G7 to C Major.

And so, at its most fundamental level, at its base, that’s what a 5-1 progression does. That’s why the dominant chord sounds like it wants to resolve to the tonic chord, because of this tritone that wants to resolve inwards. And this same tritone to can also resolve outwards, to the B flat and the G flat. And that’s also a 5-1 chord progression, and it’s effectively a D flat 7 going to a G flat major, which is the tritone substitution of the G7 to the C. And this tritone is really the basis of all tonal music. So that is, it has a tonic, which is what makes this tonal music. And all the other chords in that key want to move into or resolve into that tonic chord. And this tritone interval is precisely what makes that dominant feel like it wants to resolve into the tonic. Now, modality or modal harmony, on the other hand, is like the US Declaration of Independence for music: All chords are created equal.

Now, modality has the following features: It uses all of the available modes. It doesn’t just use major and minor keys, it also uses Dorian, Phrygian, Lydian, and all the other modes that exists. It also does not have a functional harmony. However, it does still have a tonal centre. Now, similarly, let’s just break that down now again. Modal music does not just use major and minor keys, it also uses all of the different modes as keys. So, for example, you can have a song in the key of D Dorian. Chords do not serve a harmonic function, so you don’t have to worry about classifying chords as predominant, dominant, or tonic, like you would in tonal music. However, there is still a tonal centre. So, as I just mentioned, a song can be in the key of D Dorian with the note D being the tonal center, that is the root note. But because there is no functional harmony, the chords do not feel like they need to resolve or move to that tonic chord or the D minor 7 chord.

Each chord just floats there by itself as a standalone entity, and you can, sort of, go to any other chord. You can just jump around from chord to chord without any regard to the function of each chord, because chords do not have function in modal harmony. Now, this is actually quite difficult to achieve because whenever you play that tritone, you, by definition, create a dissonance which sounds like a Dominant 7 chord, and feels like it wants to resolve to the C Major or the tonic chord. Thus, you’re turning the music tonal. So, when you’re playing modal music you really have to be careful when using this tritone interval, because this tritone is precisely what makes tonal music sound tonal; which is the opposite of what we want.

So it’s really a delicate balance. You still want D to sound like your tonal centre, if you’re in the key of D Dorian. But you can’t do it by using the function of chords. So, for example, you can’t use the chord A7, which would be a kind of secondary dominant, to take you back to the chord D minor 7, that is, the tonic chord, because then it sounds tonal, which is what we want to avoid.

You also want to be careful using the chord G7 and B half diminished because they’ve got that tritone interval and suddenly your song sounds tonal. And so, it sounds like it wants to resolve to that C. So, instead of using the diatonic function of chords to establish the root, you have to use other techniques, such as: pedal points or repetition of the root note. So, essentially just by playing D repetitively. Maybe going back and forth [music] You’re establishing this as the tonal centre, as the root note. Or you could do something called an ostinato, which is essentially just a pattern that you repeat over and over and over again that focuses on that root note. So something like [music] So because I’m repeating that note D, the root note, on the first beat of each bar it, sort of, establishes that as the tonal centre, as the root note. So, essentially you want to emphasize the root note in the bass and then avoid playing that tritone, either in the chord G7 or B half diminished in your right hand. And so, because modal chords don’t have functions, they don’t really have to go anywhere.

They don’t have to go back to the tonic. They just float around and so you don’t really know where they’re going to go. And it’s not really important where they go. And so you’ll find that most modal songs don’t have chord progressions. They just have a key or a scale or a mode listed, like, for example, D Dorian. And then no chord progression or no chords that you have to play. And so then really, it’s up to you. You just move around the chords at random, but try to do it relatively smoothly. You want to avoid playing that tritone. So, for example, in the G7 you can just play a G triad instead of the G7.

Therefore you avoid that tritone interval. And you want to generally avoid playing the B half diminished, or even the B diminished triad. Because again it’s got that tritone there. And you want to keep it relatively simple. So not too busy; not too many chords; a little bit on the boring side. So the chords are really just there as a harmonic underlay over which the soloist would improvised. [music] Right, or something like that. So you’re emphasizing the root in the bass note. You’re just playing random diatonic chords up here, but nice and smoothly and avoiding that tritone interval.

Now, because the majority of music we hear day to day is tonal, and the chords are usually built out of stacked thirds. We’ve generally learned to associate chords built out of thirds with tonal harmony. Now, this creates a problem for modal songs because we explicitly want to move away from tonality. And so, the way around this is to play chords built in fourths, that is, quarter harmony. And this is exactly what Miles Davis and Bill Evans did on the classic modal jazz song: So What.

Now, I’ve got a separate video on quartal harmony and on the So What chord if you want to learn a little bit more about that. But essentially, by building chords in fourths rather than thirds, you break that tonal anticipation of the dominant chord wanting to move to the tonic chord. And you create music that’s a little bit more ambiguous and vague and modal. [music] Right, or something along those lines. So building chords in fourths rather than thirds. But again, you really want the bass to emphasize that tonic, the D, often. So that you have a reference point and create a tonal center, so the song sounds like it’s in D Dorian. Otherwise, because the chords have no function and if you stop reinforcing the root note in the bass, then you completely lose that sense of the song having a tonal center and that’s not what we want from modal music.

That’s, sort of, moving more towards that atonal harmony. But again, I’ll leave that for another video. So, modal harmony creates a more ambiguous and vague sound and is now considered much more modern than traditional tonal harmony. So modal harmony completely changed the way people think about jazz and about improvisation. And it led to the creation of Modal Jazz with Miles Davis’s ‘Kind of Blue’ album considered the epitome of Modal Jazz. And, in fact, this is why so many people consider ‘Kind of Blue’ to be one of the greatest Jazz albums of all time.

It was hugely influential, and this modern sounding modal sound is now used by many many jazz musicians the world over. And modal harmony has very interesting implications for improvisation. Playing these sort of, vague, ambiguous chords underneath, essentially gives the soloist much greater freedom and much greater choice. And this was precisely the idea behind modal harmony and Modal Jazz. But I will leave all of that for another video. Thanks for watching guys. Again, feel free to leave any questions or comments. See you..