On your piano, you can play more than one note at a time, giving it the coveted distinction of being an instrument capable of harmonizing. Sure, other instruments in a band or orchestra can play collectively to form harmony, but you can harmonize all by yourself with a piano.
Playing many notes simultaneously is the essence of harmony. The notes you choose and how you arrange them around the melody determines the kind of harmony you produce, whether you use many notes or just one note with each hand.
The distance between any two musical notes is called an interval. You need to understand the concept of intervals and the notes that make up each interval so that you can identify and select the right notes to build harmonies. But you also use intervals to identify and build notes in a melody. As you play or sing the notes of a melody, the melody can do one of three things: It can stay on the same note, it can go up, or it can go down. When it goes up or down, the question of how much leads to the subject of melodic intervals.
You measure an interval by the number of half-steps and whole-steps in between the two notes. But because this method involves lots of counting, memorization, and complicated arithmetic, I have an easier solution: Use the major scale as a measuring tape.
Pick two notes and count the scale notes (not the piano keys) in between to find the name of the interval. For example, if you play the first note of the C major scale (C) followed by the fifth note (G), you just played a fifth interval. If you count the scale notes in between C and G, you get five — C, D, E, F, G. From C to E (the third note in the scale) is a third interval, and so on. Not much originality in these names, but is this easy or what?
You don’t have to start with the first note of the scale to make an interval of a fifth. This concept of intervals is all about distance. You can build a fifth on the note G by climbing up five scale notes to D. It’s easy to check yourself by counting the scale notes in between.
Exploring the types of intervals
Like scales, intervals come in different varieties: major, minor, perfect, diminished, and augmented. Knowing these classifications helps you identify and build harmonies for the music you play. For example, if you want to build a minor chord to harmonize with a melody, you must use a minor interval.
Here’s your guide to making different types of intervals:
Major interval: Measure a major second, third, sixth, or seventh by matching the second, third, sixth, or seventh notes of the major scale and counting the half-steps from the root note.
Minor interval: You can make a second, third, sixth, or seventh interval minor by lowering its major counterpart a half-step.
Perfect interval: This label applies only to fourths, fifths, and octaves.
Diminished interval: You can make any interval diminished by lowering it a half-step.
Augmented interval: You can make any interval augmented by raising it a half-step.
In an eternal attempt to be lazy, er, efficient, musicians use the following abbreviations when discussing intervals:
M for major intervals
m for minor intervals
P for perfect intervals
dim for diminished intervals
aug for augmented intervals
Numbers for the interval size, as in the number 5 for a fifth
So, when you see P5, you know it means a perfect fifth. When you see M2, it means a major second. When you see m6, it means a minor sixth.
Intervals can be measured upwards or downwards. That is, when you play a C-G fifth interval, you can say that G is a fifth above C or that C is a fifth below G. So, a descending interval is measured from the top note to the bottom note. Likewise, ascending means . . . oh, you can figure that out.