[MUSIC] Okay, so that's how chords work. Let's talk more about these triads, those essential building blocks of music. We have three primary triads, as said, the tonic, built on the first degree, the scale, the dominant build on the fifth pitch of the scale, and the subdominant built on the fourth pitch or degree of the scale. These chords account for a surprising amount of the harmony that we hear. Let's take a common tune, Jingle Bells. Let me just play Jingle Bells and keep the chords steady underneath, the triads. [MUSIC] Tonic. [MUSIC] Subdominant. Tonic. [MUSIC] Dominant. Tonic. So those triads keep changing underneath the melody. But why do they change underneath the melody? Why can't we just harmonize the melody using one chord, one triad? Well, if we did, here's what would happen. [MUSIC] And so, doesn't really work, does it? We violated one of our rules of musical syntax. Harmony must change to fit the melody. As a melody moves through the pitches of the scale, it moves in and out of the pitches at different triads. If a melody pitch is part of a triad, we have a consonance. But if it moves out of that triad, then we heard a dissonance. We have a dissonance. So the melody much change to be harmonious with, sound good with the melody. When triads change, bringing a consonance support to a melody, they build up a certain momentum, they come in a purposeful way, a purposeful march, that works in sync with the direction of the melody. Chords moving in this purposeful fashion create what we call a chord progression. They seem to pull along, one to the next, moving toward and eventually arriving at the tonic, the tonic triad, the home triad. Let me play a chord progression. [MUSIC] So that's a very straightforward chord progression. The end of a chord progression is called a cadence, a fall, the final move, built possibly on the fourth degree of the scale that goes to the fifth degree of the scale that ultimately moves to the tonic. As you can see on the screen here called four, five, one or subdominant, dominant, tonic. Same sort of thing. Let me play that for you. [MUSIC] So that's a cadence, a fall to the end. Remember that flashy end of the opening Richard Strauss's Zarathustra from our first session. It ends this way. Remember this melody? [MUSIC] But the final cadence goes, [MUSIC] That's just another cadence, another end of the musical phrase, end of a passage with a chord progression. Often in classical music, the composer will signal the termination of a piece by alternating five and one triad, dominant and tonic triads. It's a very simple cadence, goes this way. [MUSIC] Something like that. The end, the end, the end. You might just as well hold up a sign. Hold up a sign like this. The end. So you can have a visual sign that conveys meaning. These letters allow us to generate a sound that conveys meaning. A word is part of a language. Or you can have a musical sign that also conveys meaning. Music, too, is a language of music. The end. This kind of fifth degree to tonic degree or one degree, five, one cadence moving tonic to dominant again or subdominant, dominant, tonic is called an authentic cadence and is most common in Western classical music and equally common in Western pop music. Here's another kind of cadence, it's called a deceptive cadence. Here the composer fools you, makes you think that you're going to go home to the basic tonic. But he sort of kidnaps you and takes you away somewhere else by substituting at the last moment another point of arrival for the tonic that you expected. Let me play a deceptive cadence here for you. Let's see. [MUSIC] Oh, that wasn't expected. Or it could go, [MUSIC] Oh, that was even more unexpected. So although you've been aurally kidnapped here, spirited away somewhat unexpectedly to a new musical chord, there's good news. You will be rescued. A piece that moves to a deceptive cadence invariably will work its way back to the tonic. After the deception, the piece has to keep on going until it reaches some kind of authentic cadence. Almost all music has this kind of happy ending. Having been deceived by the musical world, the musical traveler must now arrive back at home. So after a deceptive cadence, [MUSIC] Maybe continuing. [MUSIC] Ending up with some sort of authentic cadence. There's a third kind of cadence to which we apply the nickname amen because it's used in much religious music, particularly music of the hymns of the church, the ending of hymns, and hymns in universities as well. They're sung at commencement or whatever. An amen cadence is one that you'll likely recognize. It moves from a chord build on the fourth degree of the scale to one built on the first degree of the scale. [MUSIC] And you can here people singing the Hebrew word amen. Finally, the last of our four cadence types, the half cadence. Here the music just seems to stop, specifically on a dominant chord. The music seems suspended, but at the same, it implies that we have to move on more. Maybe we should call it then a pause cadence because that's really what it wants to do. It pauses momentarily freezing the action. Hold it right there, and then it moves on. Let me play a half cadence. Let me see if I can find that Beethoven that we heard earlier. So here's the Beethoven, he's coming along. [MUSIC] And you want to hear, [MUSIC] And indeed, he gives us that. But that moment we pause there, that's a half cadence, that's a pause cadence. So let's review, with me playing a standard chord progression. Indeed, the Pachelbel Canon Harmony, and I'll work through all four cadential types in one way or another. Let me try this. What key? Let's try this key. [MUSIC] Mm. Well, that would be our deceptive cadence. We could try it again. [MUSIC] Just stop there, and that would be our pause cadence, our half cadence. Or we could continue on. [MUSIC] Come back home, that'd be our authentic cadence, or we could go, [MUSIC] So cadences have their own emotional vibe to them. But they also help tell you where you are in the music. If you hear this, [MUSIC] Or this. [MUSIC] You know darn well that you're at the end.
