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So I wanted to give a high-level overview of Jazz Theory in one short video which generally explains how everything fits together. Now, naturally, this requires some generalizations so forgive me for that in advance. But here we go. Now, there are 12 notes in an octave and the distance between two notes is called an interval. Now don't forget this because all music theory can be broken back down into notes and intervals. Now, Axiom number one:
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There are two types of intervals: dissonant intervals, which sound harsh and jarring, like the semitone or the tritone; and consonant intervals, which sounds nice and pleasant, like the perfect fifth and a major 3rd. Now, the reason some interval sound consonant while other sound dissonant has to do with the Overtone Series. But that goes beyond the scope of this video. Which brings us to Axiom 2a: Dissonant intervals create tension which sound like they want to resolve to
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consonant intervals. But more on that later. Now a scale is simply some subset of these 12 notes. And there are literally thousands of possible scales. But for historical reasons the most commonly used scale is the major scale, which has seven notes [scale]. Now, scales have two components: the notes that they're comprised of; and their Tonal Centre or Root Note. Now the Tonal Centre is the note that feels completely resolved and at rest. For example, if I play the following phrase [scale]
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Right, that sounds unfinished and unresolved. Your ear expects one more note for that little phrase to sound finished and resolved. And that note is the note C, which is our Tonal Centre Now, a Tonal Centre center can be established in a number of different ways. It can be the first note or the last night you play; the highest or lowest note you play; the loudest note you play; the note you repeat most either through pedal point or ostinato; or some kind of other emphasis
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of the Tonal Centre, of that note. But once you've established a particular Tonal Centre, all other notes are heard in relation to that Tonal Centre including notes inside and outside the scale. And each of the twelve notes creates a certain level of tension or dissonance through their implied interval with that Tonal Centre and therefore creates some tendency to resolve to that Tonal Centre. Right, remember Axiom 2a. Now, if you keep all the notes of the
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scale the same but you change the Tonal Centre, you create a new scale or 'mode'. So, for example, C major has all the same notes as A natural minor, just a different Tonal Centre. Similarly, C Ionian, D Dorian, E Phrygian, F Lydian, and so on, all share the exact same notes, they just have different Tonal Centres. Now, modes are just a different way of thinking about music and keys. They allow us to allocate every
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single chord a particular scale, which is a useful way of thinking about music, and especially Jazz music. Now, scales and chords are interrelated. There are two sides of the same coin. A scale is a horizontal representation of a particular collection of notes. And a chord is a vertical representation of that same collection of notes. And scales are built in seconds while chords are built in thirds. So for example if we take all the white notes and we go up in seconds or in steps [scale]
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We have the C major scale. And if we take all the same, that is, all the white notes, but we go up in thirds then we have [chord] the C Major 13 chord. Similarly if we take all the white notes except for B flat and we go up in seconds, starting and finishing on the C [scale]. We have C Mixolydian or F major just starting and finishing on the C. And if we take those exact same note and go up in thirds [chord], we have the C Dominant 13 chord. Or again, taking all the white
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notes except for the note F sharp, starting and finishing on the C. Going up in seconds [scale] gives us the C Lydian mode or G major. And going up in thirds [chord] gives us the C Major 13 sharp eleven chord. Right, so the C Major Scale has all the same notes as a C Major 13 chord The C Mixolydian scale has all the same notes as a C Dominant 13 chord And the C Lydian Scale has all the same notes as a C Major 13 sharp eleven chord
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So, then these are the scales that you would use to improvise over these chord. Now, the degrees of a scale or chord are based off the major scale and then just repeat an octave higher, And any alteration to these degrees are alterations of the notes of the major scale. So for example taking the scale C major The D is both the 2 and the 9. The F is both the 4 and the 11. The A is both the 6 and the 13. The D flat is both the flat 2 and the flat 9
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The F sharp is both the sharp 4 and the sharp 11. And the A flat is both the flat 6 and the flat 13. And in theory, you play every single degree up to the degree listed in the chord, taking any alterations into account. So, for example, In a C13, you play all the way up to the 13. In a C9, you play all the way up to the nine. In the C7, you play all the way up to the seven In a C13 flat nine sharp eleven, you play all the way up to the 13 with a
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flat 9 instead of a natural 9, and a sharp 11 instead of the natural 11. Now, in practice we treat chords a little bit differently but I'll get into that in a bit. So just like you can keep all the notes in a scale the same but change the Tonal Centre to create a new mode. You can also keep all the notes in a chord the same but change the root note to create a new chord. So taking all the white notes again we can have the chord C major 13, from the D we can have D
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minor 13, from the E we can have E minor 11 flat 9 flat 13, or F7 sharp 11 or G13 Right, all of those chords use all of the notes in the C Major Scale. That is, all the white notes just from a different root note. And because all these chords use only the notes from the key of C major, that is, all the white notes. All of these chords are in the key of C major and so you can use the C major scale to improvise over them. But even though a chord can be extended all the way out
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to the 13th, in Jazz, the basic chord is a seventh chord, that is, just the first four notes. Now there are four basic 7th chords: a Major 7 chord, or a Dominant 7 chord, a minor 7 chord, or the minor Major 7 chord. Now there are also diminished 7 and Augmented 7 chords but these work a little bit differently. And each 7th chord has a particular feel or sound. For example, the Major 7 chord sounds happy or calm. The Dominant 7 chord sounds tense. The minor 7 chord sounds
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sad. And the minor Major 7 chord, which is a little bit less common, is a kind of confused sadness. Now each of the degrees in a chord can be categorized and analyzed. The first four notes, that is, the 1, 3, 5, and 7 are called 'chord tones', because they make up the notes of the basic 7th chord. Now, the 3 and the 7 are a subset of the chord tones which are called 'guide tones'. And the other three notes, that is, the 9, 11, and 13, are called 'tensions'. Now, the 1 or the root note
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establishes the tonality of the chord. For example, C Major 7 or D Major 7 or E Major 7 and so on. So you can't alter the root note of the chord without changing the type of chord that it is. And by alter, I mean you can't flatten or sharpen the note. The 3 and the 7, that is, the guide tones, establish the quality of the chord, that is, whether it's a Major 7, a minor 7, or a Dominant 7 So again, you can't alter the 3 or the 5 of a chord without changing the
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type of chord that it is. The 5 establishes whether the chord is diminished or augmented and you can generally alter the 5 without affecting the chord too much. And the 9, 11, and 13, that is, the tensions, just add colour to the chord. So you can alter these without affecting the type of chord that you're playing. So by this I mean that a C9 is still a C7 chord, just with an added tension. A C13 flat 9 sharp 11 chord is still a C7 chord just
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with some altered tensions. A C7 flat 5 or a C7 sharp 5 is still generally a C7 chord. But a C minor 7 chord or a C Major 7 chord is not a C Dominant chord because we've changed the third the seventh. And similarly a C sharp 7 chord is not a C7 chord because we've changed the 1, the root note. So, you can alter the 5, 9, 11, and 13 of a C7 chord and this chord will still be a C7. But if you alter the 1, the 3 or the 7, this chord will no longer be a
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C7 chord. It'll be some other chord. Now, the 3 and the 7 are the most harmonically important notes in the chord because they establish the quality of the chord. The 1 and the 5 are less important. And the 9, 11, and 13, that is, the tensions, are even less important. Now, just like each of the twelve notes creates a differing level of tension against the Tonal Centre in a scale; each of the twelve notes also creates a differing level of tension against a
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particular chord, and these can also be categorized. Now first let's look at Non-dominant chords. So the 1, 3, 5, and 7 are the chord tones and they're very consonant because they make up the chord and therefore provide a high level of resolution. The chord tones plus one semitone are called 'avoid notes' and they're very dissonant and create a high level of tension. The chord tones plus two semitones are called 'available tensions' and they
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give a slightly consonant sound and a low level of resolution. And all the other notes provide some dissonance and a low level of tension. Now Dominant chords are a little bit different. The non-guiding chord tones, that is, the 1 and the 5, are very consonant and create a high level of resolution. The guide tones, that is, the 3 and the 7 are also very consonant and create a high level of resolution. The guide tones plus one semitone are avoid notes and are very
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dissonant and create a high level of tension. And all the other notes are available tensions and they create some dissonance and a low level of tension. Now when we build chords we can only use chord tones, obviously, because they make up the actual 7th chord, and available tensions. Now, this is because available tensions are thought to retain the general feel of the chord, so for example a C major 9 [chord], which is an available tension, still feels like a
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C Major 7 chord, it still feels calm and happy Whereas avoid notes do not retain the same feel, so C major flat 9 [chord], no longer feels like a C major 7 and no longer feels happy and calm. It feels kind of angry and confused. So then a C major 13 chord, for example, exists in theory but not in practice because of the natural 11, that is the F, is one semitone above the chord tone, which is the third, and therefore an avoid note
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and therefore cannot be used. And so then that chord, while it exists in theory, does not exist in practice. Whereas a C major 13 sharp 11 [chord] has an F sharp, which is 2 semitones above the chord tone, and therefore an available tension, and therefore it can be used. So then the C major 13 sharp 11 exists both in theory and in practice. Now C major 13 chords do actually exist in practice, but I'll explain why in a moment. And so then, when you're improvising, if you play or target a
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chord tone, especially the guide tone, it will sound very pleasant and consonant and resolved. Whereas if you play an avoid note, it'll sound very dissonant and create a lot of tension which will then sound like it wants to resolve, usually to a chord tone and if you play an available tension, it'll sound somewhat consonant and resolved but not as much as a chord tone. But again, more on this later. So because not all notes in a chord are of equal importance
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it's possible to omit certain notes to create shell chords and substitute chord. So it's possible to retain the same feel of a chord without playing all the notes in that chord. The most important notes in a chord are the guide tones, that is the 3 and the 7, again because they established the quality of the chord. So just playing these two notes by themselves creates the general feel of the chord. So for example just playing E & B sounds like
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a C Major 7 chord. And just playing E and B flat sounds like a C Dominant 7 chord Now this is called a shell chord because it's only the shell of the whole chord. Now this, of course, depends on context and all the surrounding chords in the chord progression, but more on that in a moment. So for this reason when you come across a C Major 13 chord or a C Dominant 13 chord, the natural 11, which is an avoid note, is generally omitted. So then
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a C major 13 chord does exist in practice. It just implicitly omits the 11. Now for this same reason chords can be substituted. If the substitute chord contains the 3 and the 7 of the substituted chord, the two chords will have a similar feel and so can act as viable substitutes for each other. For example E minor 7 and A minor 7 can both substitute for the chord C major 7. D flat 7 and B diminished 7 can both substitute for G dominant 7. And
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E flat major 7 can substitute for the chord C minor 7. But substituting chords and omitting notes are really the same thing. To use the cliche again, they are two sides of the same coin. So we can omit any note other than the 3 and the 7 without affecting the feel of the chord. So this means that we can omit the root. So then if we take a C Major 9 chord, which is an extended C Major 7 chord, and we drop the root note, we get an E minor 7 chord, which is a substitute chord for that
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C Major 7. So an E minor 7 is a rootless C Major 9. And so we find that a sad chord, the E minor 7, also sounds like a happy chord, the C Major 7 Which is interesting. And for this reason chords are very ambiguous. They depend on the note that's being played in the bass and on the chord that's played before and after that particular chord. For example, let's take the notes E G A and C. Now, these four notes can be a C6 chord, an A minor 7 chord, or a rootless
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F Major 9 chord. And the only way to tell the difference is by looking at the chord progression and at the bass note. Now the most common chord progression that establishes the tonic chord is a 5-1 perfect cadence. So if we have a G7 going to that collection of notes with a C in the bass, then we have a C6. If we have an E7 going to that collection of notes with an A in the bass, then we have an A minor 7. Or if we have a C7 going to that collection of notes with an F in
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the base then we have an F Major 9. Now, the feel of the chord also determines its function. To discuss functionality we need to discuss another dissonant interval: the tritone, which literally means three tones. Now, there's only one possible tritone in the major scale and that is between the fourth and the seventh of that scale. Now this is called the diatonic tritone. And the diatonic tritone dictates something called the function of a chord. So if we take the
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C Major Scale then the diatonic tritone is between the F and the B. Now if a chord doesn't contain the note F, it has a tonic function, like the chords C Major 7, E minus 7 and A minor 7. And tonic function chords give a high level of resolution. If a chord contains both the F and the B, so both notes in the diatonic tritone, like the chords G7 and B half diminished, then that chord has a Dominant function and a high level of tension. And if the chord only has the
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note F in it, like, for example, D minor 7 or F Major 7, then it's a pre-dominant function chord and gives a low level of tension. Now remember Axiom 2a: Dissonant intervals want to resolve to consonant intervals. So the diatonic tritone, which is a dissonant interval, in the dominant chord feels like it wants to resolve to the major third interval in the tonic chord in the one chord. Now, this creates a 5-1 perfect cadence and establishes the one
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chord as the tonic chord, and this is the very basis of tonality and of functionality. And so the same way that you establish a tonal centre in a scale you can also establish a tonic chord using this 5-1 relationship. So, for example, take the following chord progression [music] Right, that sounds unfinished and unresolved because we're expecting to hear that C major 7 chord. Without it this progression sounds unfinished. So the C major 7 chord is the tonic chord.
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So the same way that the tonal centre of a scale feels resolved, the tonic chord in a chord progression also feels resolved. Now we can take Axiom 2a and go a little bit further to create Axiom 2b (there was always going to be a 2b) and this states that: slightly dissonant intervals and chords want to move to very dissonant intervals and chords which want to resolve to consonant intervals and chords. So this means that a general chord progression would typically
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go from a pre-dominant chord to a dominant chord then to a tonic chord. And this brings us to the basis of most traditional tonal music in existence. So a typical tonal chord progression could be a 2-5-1. Which is one of the most common chord progressions found in jazz. So the pre-dominant chord feels like it wants to move to the dominant chord, which in turn feels that it wants to move to the tonic chord And again, this is where context is important. For example, if we take the
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chord progression D minor 7 flat 5 going to G7 going to C major 7, then that D minor 7 flat 5 chord is functioning as a pre-dominant chord, so it's effectively a minor 7 chord just with a flat 5.
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Whereas, if we take the chord progression F Major 7 going to B minus 7 flat 5 going to C major 7, then that minor 7 flat 5 chord is functioning as a dominant chord, right, because it's between a pre-dominant chord and a tonic chord. So context really matters when analyzing chord progressions and a single chord on its own is really hard to analyze and understand in any meaningful kind of way. You really have to look at the entire chord progression in its entirety, that
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is, the chords that came beforehand and the chords that came afterwards. And so this movement of pre-dominant wanting to go to dominant wanting to go to tonic exists because of the Diatonic Tritone, because of functionality, because of Axiom 2b, and also because of something called voice leading. So there are really two aspects to any given chord progression: the chords themselves, and how the chords transition from one to the next. And this transition to the next
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chord or through the chord progression is affected by voice leading. Now notice when each chord transitions to the next in a 2-5-1, 2 notes stay the same and these are called common tones, and two notes moved by step. And so this brings us to our third Axiom: When moving between chords, the more common tones you have and the smaller the movement between non-common tones, the smoother the chord movements will be. And so this 2-5-1 chord progression can be extended further to
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go around the circle of fifths in a particular diatonic key. And this is known as a circle progression which is also very common in Jazz. So starting on the F rather than F sharp, again just to stay in the key of C major, then moving to the B, to the E, to the A, to the D, to G, to C, playing all the chords in the key of C major, going down in fifths, creates a really smooth chord progression. And as I mentioned before, moving down in fifths is the basis and the essence of traditional
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tonal music. Now, remember that a chord extended out all the way to the 13th has all the same notes as its own diatonic scale, so you know exactly which scale to use when improvising over that chord. So again a C Major 13 with that natural 11 has all the same notes as the C Major Scale, even though that particular chord doesn't exist in that form in practice, that is, the 11 is usually omitted, as I said before. Well 7th chords are a little bit more ambiguous because they're missing a few
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notes. Two of the scales I gave earlier were the C Major Scale and the C Lydian Scale or the G Major Scale. Now, both of these scales have the notes C E G and B in them, so the chord C major 7 can be created from both scales. So if you just play the 7th chord both those scales fit over the C Major 7 chord. So both can be used to improvise over the C major 7 chord and in fact the C Lydian Scale will fit better, that is, be more consonant, because it avoids that
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F note and instead has an F sharp. So that means when improvising you can use any scale over a particular chord, as long as that scale has all the notes found in that particular chord. Now, it's actually a little bit more complex than this but, that's the general idea. And that gives you heaps of options to choose from. So again, taking a 2-5-1 in the key of C major. So having a D minor 7 to G7 to C Major 7, we could use the D Dorian, then G Mixolydian, then C Ionian
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mode. Or D Aeolian, then G Wholetone, then C Lydian mode. Or D Blues Scale, G Lydian Dominant, and then C Lydia augmented. Right, and this is the benefit of thinking in terms of modes. You can allocate each individual chord and number of different scales, all of which you can use when improvising. So that's the theory bit, but now in practice, playing chords built up in thirds, that is, playing block chords, is considered a bit simplistic. So in jazz
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we use more sophisticated chord voicings. So you're still playing the same notes, but in a different order, with different intervals, and across a number of octaves. Now, as a general voicing rule, use wider intervals at the bottom and narrower intervals at the top. So, for example, you could play a C Major 13 chord like this [chord]. Which omits the 5 and the 11. Another chord voicing often found in Jazz are Quartal chord voicings. So building chords up in intervals of
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fourths rather than thirds. So again playing that C Major 13 chord using a quarter voicing could look like this [chord] So again that's omitting the 11. Now, in Jazz you're really doing one of two things. You're either in the rhythm section and playing the chords, or you're improvising, or you're doing both with your left hand playing chords and your right hand improvising. Improvisation is all about creating tension and then resolving that
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tension. Now you create tension by playing dissonant notes, that is, avoid notes. And you resolve tension by playing consonant notes, that is, chord tones and available tensions. Now there's a million different ways to do this but that's essentially the underlying idea. And so that, in a nut shell, is a high-level overview of basic Jazz Theory. Now, that was largely harmonic theory, and I didn't really talk about meter or rhythm, which in Jazz is usually 4/4 and swung. And I
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also didn't talk about form, which is usually a head-solo-head structure or form with the head being either a 12 bar or 32 bar length. But then, essentially, that's really what it comes down to. Playing Jazz requires playing chords, and then improvising over those chords. And it's all about creating tension with dissonance and then resolving that tension with consonance, while doing those two things. So when you're improvising you can use particular notes from particular
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scales to create dissonance and consonance based on the interval that note implies with the Tonal Centre of the scale; and with the underlying chord being played. So, for example, if I was playing the C Lydian Scale over a C Major 7 chord, and I play the note F sharp. That creates a certain level of tension based on this note's, the F sharp's, relationship with the tonal centre of C and the chord C Major 7 that i'm playing. And if you're playing the chords you create dissonance
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and consonance through the chords themselves, by using various extensions and alterations and available tensions; and through the chord progression based on the function of each chord that you're playing and how smoothly transition from each chord to the next. So, that is, based on functionality and based on voice leading. So again, if you have a C7 chord, you can add a sharp 9 which adds tension to that chord. And instead of moving to the tonic chord, the
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F major 7, you can continue playing dominant 7 chords, and not really resolve that tension that that Dominant chord is creating to a consonant and resolved tonic chord. Now, everything I've explained here relates to more traditional tonal jazz, like Swing or Bebop or Hard-bop or Cool jazz. Your more modern jazz, like Modal jazz and Free jazz and Post-bop or Contemporary jazz is all about breaking these rules, by doing things like: creating chords with avoid notes [chord]
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Or creating non-functional chord progressions
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Using non diatonic scales, like symmetrical scales or synthetic scales, like the whole tone scale, the diminished scale, the Augmented scale; and creating songs without chord progressions or without chords. But, of course, you have to know the rules in order to break. Cool, and that is my high-level overview of Jazz Theory. Now, I intentionally rushed through that pretty quickly because, like I said, I wanted to give a high-level overview of how it all
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fit together, how it all sits together. And I, of course, have separate videos on each one of those topics that I covered in this video. But that's it for me. As always, feel free to leave any questions or comments and thanks for watching. See you.
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