In the first week of class, I showed you a chord chart. At first, maybe it was a bit hard to comprehend it, but I showed you how it essentially outlines the kinds of chord progressions that you find in classical music. And we saw some features of classical music, like everything leads back to one, that usually you have a five before you go to one, a dominant chord before you go to one. That the circle of fifths, for instance, was very important. And there's one more thing that that chord chart shows, and that is that substitution is possible. We saw on the right-hand side of that chart that there was a four chord, and underneath it a two chord. A five chord, and underneath that a seven diminished chord. So, in this week four I want to talk about diatonic substitution, and how we can actually make harmonic progressions more interesting by using substitutions of chords rather than the chords that we've always been using. Let's start off with the 1-5-1 chord progression. In the end what we're going to try to do is substitute the five chord for a seven diminished chord. Well let's first look at these chords next to each other, and understand why it is that we can actually substitute them. I'll do this here. If I take the [MUSIC] sorry. If I take that chord, and then I take [MUSIC] So this is the five chord and this is the seven diminished chord. Allright, we're in D minor again. What do I see? Well first of all, I see that I have two common tones. In fact I can do this. [SOUND] To show that we have these two common tones. Oops. [MUSIC] And we have one chord, one chord tone, one note, that's different between them. [MUSIC] And interestingly, if I bring this one down, which I can do this right here. [MUSIC] We see that they're only a step apart. We also see that this note itself is actually the seventh of a dominant seventh chord. So, [MUSIC] There's your dominant seventh chord in third inversion. That is this would be a five four two chord. So we see how many similarities there are, in fact... [MUSIC] let's take this. Let's, let's give ourselves a one chord here. Whoops, not what I wanted. [MUSIC] Let's give ourselves a 1 chord. And then let's make a 5 chord. And then let's go back to the one. And then let's just cut and paste this thing. This is a 7 diminished triad, right? If I put it here, then I get a dominant 7th chord. Yeah, root 3rd 5th 7th. And then we resolve it [MUSIC] Back to there. Sorry, I'll do this quickly. [MUSIC] Like that. Here's our leading tone, it should actually go up here, but it's in an inner voice, so we'll have it jump down. Also, this is keyboard writing. In keyboard writing, this is completely fine. Good. So we see what a close similarity there is, what a, a close kinship, so to speak, there is between the five chord and the seven diminished chord. So let's try to use this seven diminished chord instead. Let's, let's use this upper part, but not have the root of the five chord. So how do we do that? Well, let me give an example. The first thing I want to say is the following. [SOUND] This thing, where you get root position five chord. [MUSIC] You don't see much. Let me show you why. Let's go to this chord. Let's voice lead it appropriately. [MUSIC] We'll get this double leading tone, so we don't want that. We want to avoid having double leading tone. Why? Because leading tones, look they're in the outer voices, right. This is a particularly bad example, I mean, there are cases where you could avoid this. So I'm, I'm sort of setting up a situation that demonstrates the worst that you could possibly do. So you've got these outer voices that are both leading tones, which forces them to resolve both to the tonic, which means we need to do this. [MUSIC] And we immediately get parallel parallel octaves. Okay, so what do we do instead? Well, let's do this. So, maybe I do, I throw in some roman numeral, roman numerals here. We're in the key of D. Sorry, I didn't write that down, but. And this is seven diminished. And this is one. And like I said, this one you're not going to see very often in root position. How are we going to see it? We're usually going to see it in [MUSIC] first inversion. Are you going to see in in second inversion? You might find it in second inversion as a kind of passing chord at times, but that's about it. So mostly, this seven diminished chord you're going to want to put into first inversion. Which makes voice leading it actually fairly easy. This works just fine. Now this thing here, though, and let me play it back for you, so you can hear. I'll go from the very beginning, so you can hear this one five one and then you can hear the one seven diminished six to one. You'll hear how similar they sound. [MUSIC] In fact, if you're not listening very closely, you might actually mistake this as some kind of five chord. Perhaps you'd hear this in the bass and say that's a five six four, for instance. They are, they have a really similar sound. Nonetheless they are different. And I should say that this one going to seven diminished six back to one. That one, you're going to see much less frequently than this. Where it does function as a kind of a passing chord. And you get something like that. And of course, we can't have this. We see we have parallel octaves here, between base and tenor, so to speak. [MUSIC] So we just have to do that. This progression, one, seven diminished six to one six where this seven diminished six acts as a kind of passing chord, this is usually how you see this. So if you're going to be using the five of the seven diminished triad as a substitute for five or five seven, know that this is probably the progression you want to use. Will you see this? Yeah, you'll see this. And even, well, much less frequently, but you will see root position seven, although again, it's, it's very, very infrequent. So, you will see this, and you could use this, but this is the one that's really characteristic of the music that we're looking at. One question that might arise then, is that well, if you, if you have a, a dominant triad that can be substituted with a leading tone diminished triad, the seven, seven diminished triad, could we not do the same thing with the dominant seventh chord and substitute that with a leading tone seventh chord, the seven fully diminished seven, let's say? And the answer is actually, yes. So, so let's, for instance, get this down here. [MUSIC]. If we build a leading tone that's the seven fully diminished seven chord, here, we see again, we have three notes in common. And then there's going to be this one that's different. And notice, just like in the last example, there was a, a step difference between the, the, the, the, A and the G. [MUSIC] If we do this, we see that there's only a semitone difference between this A and this B flat. So this is the root and this is the seventh of this fully diminished seventh chord. But what it means is if you're substituting, you just shift this from where it is, the root from where it is, up by a semitone. And in fact, you see composers play with this all the time. So, let's sort of realize it a bit. [MUSIC] Let's create a one five seven one progression. [MUSIC] Something like this, and we'll put it in [SOUND] we'll put this chord in first inversion. [MUSIC] Okay. Very quickly, I'll do some analysis. One, we have five six five, right? It's a, it's a dominant seventh chord in first inversion. And there you have it. So that's our analysis of this. And, let's say we want to substitute this. Let's hear it first. [MUSIC] Well, let's say that we want to have the substitution, instead of this five six five, we actually we want a seven fully diminished seven. That's no problem. And again, if we use the followed procedure that I just mentioned, here all you have to do is, you find the root and move it up by a semi-tone. So here, we have the root, right? . [SOUND] We move it up by a semitone. And then if we look at the intervals, we see we have the root, we see we have the third. Sorry, not if we look at the intervals, if we look at the, the notes. We have the root. We have the third, fifth, and seventh. And we have nice voice leading, as well. And of course, this is no longer this. We have seven diminished seven. And now, let me play this, so you can hear the difference between the two. [MUSIC] Its not a huge difference. That's often the case with substitutions. Its subtle, but its still very noticeable, and a certain, this chord certainly has a different color than this chord does.