I told you in a previous lesson that I would go over intervals again. Well here we are. This time I'm going to go a little slower and explain a little more about what makes intervals important and how they are used in building chords.
As I said before, intervals are the space between two notes. If we start at C and move up the C Major scale, we can label the intervals in that scale. From C to D is a major second. D is the second note in the scale. Right now I want you to alternate between the C and the D a few times and listen to how a major second sounds. A major second interval will have similar “feeling” in any scale you play it. Let's move on to the C and E, a major third. Do the same thing for that interval. Play it a few times to get a feel for it. Finishing out the intervals that make up the note of the major scale we have C to F as a perfect fourth, C to G as a perfect fifth, C to A as a major sixth, and C to B as seventh. C to C is an eighth, or an octave.
We talked about how to label the black keys in the C major scale earlier. Remember, the C Major scale is unique because it is made up entirely of white keys. In the case of C, the black keys are the notes that are outside of the major scale. For other scales use the notes that are not a part of the scale. Since the black keys are not a part of the C Major scale, when they are played as an interval of C, they are given special names. The C sharp or D flat key falls in the middle of the second interval. Since it is not quite a full second, we call it a minor second. The D sharp or E flat key falls in between the second and the third; since it is not quite a third, we call it a minor third.
As we move down the keyboard, the F sharp or G flat key falls after the perfect fourth. Because that key is more than a fourth, but less than a fifth, it is called an augmented fourth or a diminished fifth. I want to stop right here for a moment and talk about what this all means to our understanding of music.
What you have learned so far is vital to learning how to build chords. Let's take a simple C major triad. You probably remember forming that chord using the first, the third, and the fifth notes of the C Major scale. Those notes correspond to the root, major third, and perfect fifth intervals. Maybe things are starting to click in your head now, that's good. Let's press on a little further. What do you suppose happens if we play the minor third instead of the major third? The C major chord suddenly becomes a C minor chord!
Play those two chords now. C major (C, E, G) and C minor (C, E flat, G). What do you notice about how the two chords sound? Try to associate an emotion with each of the two chords. Not to over simplify or get all sappy, but the C major sounds a lot “happier” than the C minor doesn't it? By learning how the intervals relate to one another, you will have a far greater understanding of what chords you want to use in a song, or what notes you need to play to evoke a certain emotion from the listener.
I'm going to stop for now and let you play around a little with what you have learned. What I want you to do is to play the different intervals and get a feeling for the differences in how they sound. This will go a long way in helping you pick out the notes of a song by ear. In the next lesson, we'll continue down the C scale and learn more about the intervals and how they relate to chords and melodies.
Next, you can watch part two of Intervals and Octaves .