Welcome back, you theory enthusiasts! This time around, we are going to be talking about chords. These delightful, little triads have dominated the practice of music composition for centuries, despite many composers’ attempts to break away from what is called “tonality.” Tonal music has a home, and one of the best explanations of this comes from a lad who is way ahead of his age in understanding. Please take a moment and watch this.
In that song, he started with a G chord, which was his home, and also made the key of the song G-major. We are going to delve into tonality and how chords are used in a specific key, but first, let’s talk about building chords.
Remember when we talked about melodic and harmonic intervals? Well, chords are multiple harmonic intervals combined. Every chord has a root, third, and fifth. In the image below, the root note is G, the third of the chord is B, and the fifth is D.
This is a major chord; one of four triads we are going to cover. The image below shows the intervals used to make the four different triads. There are two ways you can look at these: as a stacking of two different intervals of a third, or a combination of an interval of a third starting from the root and an interval of a fifth from the root.
So how do you prefer to think of a major chord? A, or B?
At the end of the day, every chord has a root, third, and fifth. However, there are chords that have a seventh, which is either adding a note a third above the fifth, or a seventh above the root. Again, both are correct.
Wow! Look at all these new chords we have! Wait, you didn’t think you were just getting 4 different chord qualities, did you? Imagine if you added a third on top of the seventh… NO KYLE!!! They aren’t ready!! …Anyways, essentially what you have here are major, minor, or diminished triads, with either a major, or minor third stacked on the fifth of the chord. Building from the root of the triad, you are adding a M7, m7, or d7.
Listen to the differences in the chords in this video. I play four chords: (1) a major triad, (2) a major seventh chord, (3) a major triad again, and (4) a major-minor seventh chord. The visual difference between a major seventh chord and a major-minor seventh chord is small, but the difference you hear is substantial.
The minor seventh chord stands alone as the only minor triad based seventh chord. If you are wondering why I haven’t listed a minor triad with a major seventh, it is because that would actually create and augmented triad between the third, fifth, and seventh of the chord, which I don’t feel aurally holds the quality of a minor chord. It does have that wicked, James Bond sound to it though!
The half-diminished and fully-diminished seventh are easy to differentiate. One way or the other, you have a diminished triad. As far as the seventh of the chord, if there is M3 between the fifth and the seventh, it is a half-diminished seventh chord. A m3 between the fifth and the seventh is a fully-diminished seventh chord.
We are going to discuss diatonic functions, which is how these chord qualities are used in a key, but first we are going to go back to the diagram of the C-major scale. As I said earlier, you aren’t going to see an augmented triad in a key without adding accidentals (either by raising the fifth of a major triad, or lowering the root of a minor triad).
To wrap up, we are going to learn some super shorthand terms that are going to hopefully allow us to speak with some brevity. In the practice of music theory, we use Roman Numerals to define a chords place in a key, and it’s quality. Using numbers I-VII, we are able to account for the basic triads in a key. Uppercase Roman Numerals define major triads, and lower case defines minor triads. Augmented and diminished triads are marked with a +, or a º, respectively. Half-diminished seventh chords will have a ø rather than a º. So here it is, what we’ve been working towards.
Hopefully we have some good groundwork going on to where we can discuss chords in this fashion, and if I need to clear things up, comment/e-mail all your questions! Until next time, and thanks for turning on my corner!