[MUSIC] Welcome back, in the last lecture we defined triads as three note cords that are created by stacking notes that are a third apart. We said that the three notes are called root, third, and fifth. The inversion of the triad is determined by the lowest note, which is called the base note. If the root is the base note, the triad is in root position. If the third is the base note, the triad is in first inversion. If the fifth is the base note, the triad is in second inversion. The order and octave of the notes above the bass do not change the inversion, nor does the octave of the bass note. In fact bass notes are often several octaves below the other notes of the triad. Here are a few triads for you to practice on. Identify the root and position. Remember, you should memorize all the possible triads. A-C-E, C-E-G, E-G-B, G-B-D, B-D-F, D-F-A, F-A-C, so that you can tell at a glance what the triad is. I'll do the first one for you. E flat is the bass note. Is it the root? If so, the notes would be EGB. There's a C in the chord, so that doesn't work. Let's try a C as the root, CEG, that works. This triad is a triad that has C as the root, CEG, but it's not in root position. Since the third of the chord is the base note, this is in first inversion. Now you try the rest. Let's go back to our stacked thirds root position triads. If we build a triad on every note of the scale we end up with three different kinds of triads. First, notice that the interval between the root and the fifth is a perfect fifth in six of the seven diatonic triads. Only the triad built on the seventh scale degree, in major that is, has a diminished fifth between the outer notes. We'll save this unique triad for last. The triads with perfect fifths as their outer intervals differ from each other in the size of the third above the root. Three of the triads have major thirds, three of them have minor thirds. The triads with major thirds and perfect fifths are called major triads. The triads with minor thirds and perfect fifths are called minor triads. And the triad with a diminished fifth and a minor third is called a diminished triad. Although it doesn't occur naturally within the diatonic set, a triad with an augmented fifth and a major third is called an augmented triad. We don't have a label for a triad with an augmented fifth and a minor third, our ears hear it as an inverted major triad. And there is no diatonic triad that has a diminished fifth and a major third. Here are all four triad types built on a root of C. Notice that the diminished triad has a minor third, C to E flat, and another minor third on top of that, E flat to G flat. The minor triad has a minor third, C to E flat, and a major third, E flat to G. The major triad has a major third, C to E, and a minor third, E to G. And the augmented triad has two major thirds, C to E and E to G sharp. If you memorized major thirds when we were doing intervals, even just the white key ones shown here, you have a head start in determining the quality of triads. All major and minor triads have a perfect fifth as the outer interval, and all perfect fifths have the same accidentals, except B up to F. So B up to F sharp is the perfect fifth. So perfect fifths are A flat to E flat, same accidental, G sharp to D sharp, same accidental. F natural to C natural, same accidental, and so on. For a triad that has a perfect fifth just look at the third, if it's major it's a major triad. If it's minor, it's a minor triad, if the fifth is diminished, the triad is diminished, if the fifth is augmented the triad is augmented. You'll still need to rearrange the notes into stacked thirds root position to figure them out. Let's practice identifying a few, I have put them all in stacked thirds root position. There are one or two steps to identifying triad quality. First, look at the outer notes, the fifth of the triad. If the fifth is diminished, the triad is diminished. If it's augmented, the triad is augmented. If it's perfect, the same accidental, that is except B to F, then it's either major or minor. And we need to look at the third above the root to figure it out. In this triad, the fifth is perfect, F to C, same accidental. The third, F to A is major, so this is a major triad. For this triad, we have another perfect fifth, D to A, and a major third, D to F sharp, so this is a major triad. Here's another perfect fifth, F sharp to C sharp. The interval F sharp to A is a minor third, so this is a minor triad. Another perfect fifth, C to G. The interval C to E flat is a minor third, so this is another minor triad. Here's one of the Bs, we know that B to F is not a perfect fifth, B flat to F is a perfect fifth. And then B flat to D flat is a minor third, so this is another minor triad. F to C flat is a diminished fifth because F to C is a perfect fifth and the flat makes it a smaller interval, so it's a diminished fifth. And F to A flat is a minor third. So this is a diminished triad. B to F is a diminished fifth, B to D is a minor third. So this is another diminished triad. G flat to D natural is augmented, because G flat to D flat would be perfect, so D natural makes it wider. And G flat to B flat is major, so this is an augmented triad. A flat to E flat is perfect. A flat up to C, is a major third, so this is a major triad. Let's build some triads. I'll give the root and the quality, and we can do a few together. Build a major triad with D flat as the root. Okay, so let's figure out the fifth first. A perfect fifth up from D flat is A flat, there's the top note. And a major third up from D flat is F natural. So there's a major triad built on D flat. Let's build a minor triad on F sharp. It's going to have a perfect fifth, F sharp up to C sharp, and then a minor third, F sharp up to A natural. Let's build a diminished triad on E natural. All right so we know E to B is a perfect fifth. We need to make that interval smaller to make it diminished. So E to B flat is a diminished fifth, and E to G is a minor third. A major triad built on B natural. Here's one of our exceptions, we know B to F sharp is a perfect fifth, and B to D sharp is a major third. Finally, an augmented triad above G flat. Well we know that G to D is a perfect fifth. If we widen the interval by lowering the G, it becomes augmented, so G flat to D is an augmented fifth, then we just need a major third above G flat. We've memorized all the white key major thirds so that we know that G to B is a major third. So therefore, G flat to B flat is also a major third. That's it for triads. We learned four qualities, three of which are common. Major triads have a perfect fifth between the outer voices with a major third above the root in the middle. Minor triads have a perfect fifth in the outer voices plus a minor third above the root. Diminished triads have a diminished fifth plus a minor third. And much less common because it doesn't occur in a key, an augmented triad has an augmented fifth between the outer voices and a major third. In the next unit I'm going to talk about seventh chords. Which are just major, minor and diminished triads with another third added to the top. [MUSIC]
