In our last post we discussed the C major scale and proposed an exercise to develop your musical ear. In this article of our How to Write a Song series, we are going to learn how to construct any major scale by using its constituent intervals. At the end of the lesson you will have learned to construct the major scale on any given tone. First, we are going to study some basic concepts:
Octave:
An octave is the distance between two notes, when the frequency of one of them doubles or halves the frequency of the other. This means that an octave will sound exactly the same as the first, but it’s pitch will be higher. You can listen an octave interval here.
The Semitone or Half-Tone:
A semitone is the 12th part of an octave. It is the minimum possible interval in western music (Examples: Mi-Fa and Ti-Do). The scale containing all the 12 semitones in an octave is called chromatic scale.
The Tone:
Is any interval with a distance of two semitones. (Examples: Do-Re, Re-Mi, Fa-Sol, Sol-La, La-Ti)
Chromatic Scale:
Contains the 12 intervals of an octave. Listen it here:
Perfect Four:
Is the interval which results of adding five semitones to any given note. Listen here.
The Tetrachord:
A tetrachord denotes any three intervals that will fit into an interval of a perfect fourth. A perfect fourth is comprised of five semitones. The most broadly accepted version of the diatonic tetrachord contains two intervals of a whole tone, and one of a half-tone.
The Major Scale:
Having learn the previous concepts, it its pretty easy now to construct a major scale: it is just the sum of two tetrachords separated by a tone (contiguous tetrachords). For Example, for the major scale of Do, the first tetrachord would be Do-Re-Mi-Fa. Fa + 1 tone = Sol, so the next tetrachord would be Sol-La-Si-Do. One think to have in mind is that the first note of the first tetrachord has a distance of one fifth from the next note of the next tetrachord.
The following is the Do major scale. You can listen it here
There are million of sites on the Internet and books which will teach you the classical definition of the major scale in the form of: tone, tone, semitone, tone, tone, tone, semitone, but the tetrachord definition is far more interesting for you will use its implications in your future improvising sessions while writing new music. If you payed enough attention to the previous explanation (The distance of one fifth between the roots of the tetrachords) you will notice that there is a pattern here that you can extend until it finishes where it started. Let’s see into more detail:
If you start from Do and add an interval of a fifth sucesively, you will end up returning to Do again. This is called the circle of fifths. This circle has many applications in music composition and we will see a lot of examples in future articles. Your homework today is to construct every major scale using the circle of fifhts. We already built the Do major scale, now I’ll give you the next scale in the circle which is the Sol major. For this one we will use the tetrachord of Sol (Sol-La-Si-Do) and Re (Re-Mi-Fa#-Sol). Fa# means Fa + half tone:
Please construct the rest of the scales until you fully understand the relationships. In the following articles of our series on How to Write a Song, we’ll go deeper into more useful theory.