It’s difficult to talk about chords without also talking about how they function. In a way, I’m not even sure if it’s possible, since the language and the symbols that we use to communicate about them with often contains all the information needed about how to build them and how to use them anyway. Even so, there’s always the potential for confusion once all of those letters and numbers start getting thrown around.
When talking about chords, the base-line criteria we’re referring to is a group of three notes sounding at the same time. We call them triads, and there are four types: diminished, minor, major, and augmented. From any one of those triads we can start to piece together a sense of tonality, because each serves at least one specific role, and possibly more, in the hierarchy of functional harmony.
In the image below, we can see how the distance of the notes in relation to its root increases incrementally from each triad to the next. We might think about these triads in terms of their strength by describing this image as showing triads progressing from weakest to strongest. Even without considering specific pitches, we should be able to see how each triad might have a certain weight to it, more or less in comparison to another.
The quality of a triad is based on the sum of its parts and the order in which those parts appear. A triad consists of two 3rds stacked consecutively above the root, that when combined is equal to the interval of a 5th. In the case of the diminished and augmented triads, they are each composed of two equal 3rds, minor and major, respectively.
The minor and major triads each contain one minor 3rd and one major 3rd, with the distinction between the two based on which interval is nearest the tonic. Regardless of the order that the 3rds appear, they combine to equal a perfect fifth.
This wasn’t much fun, but I have some other posts planned that I think will be a lot more interesting and useful. Upcoming coming posts will include more ideas about harmony and using roman numerals, reading chord symbols and more about chords function. I feel like I’ve touched on most of these areas already, but mostly through examples and without much explanation.