Subdivision is a general term that means to divide something into smaller parts. You may have a home that is part of a subdivision. This means a large piece of land was divided into parts, each part was then sold to different owners, which allows multiple families to live on that land.
Musical Subdivision
Within music, the term subdivision describes thinking about a single note as having the same length of multiple smaller notes. For example, a whole note always receives the same number of beats as 4 quarter notes, and a quarter note always receives the same number of beats as 4 sixteenth notes (see Comparing Note Length for review).
The number of beats that a note receives changes based on the time signature. However, the proportion of the notes compared to each other remains the same. No matter how many beats a whole note receives (based on the time signature), 4 quarter notes will always take the same amount of time as 1 whole note.
Let’s look at our examples more closely with some different time signatures.
4/4 Time Signature
In 4/4 time, the quarter note receives 1 beat. Therefore, 4 quarter notes receive a total of 4 beats of time. A whole note also receives 4 beats of time, which means that a whole note takes the same amount of time as 4 quarter notes.
In 4/4 time, each sixteenth note receives 1/4 of a beat, which means 4 sixteenth notes receive 1 beat of time. This means that 1 quarter note and 4 sixteenth notes take the same amount of time (1 beat).
Cut Time
In cut time, or 2/2 time, the half note receives 1 beat. This means that a whole note receives 2 beats. Each quarter note receives 1/2 of a beat, which means that 4 quarter notes receive 2 beats. Therefore, a whole note in cut time takes the same amount of time as 4 quarter notes – 2 beats.
In cut time, or 2/2 time, a quarter note receives 1/2 of a beat and a sixteenth note receives 1/8 of a beat. This means that 4 sixteenth notes receive 1/2 of a beat, which means they take the same amount of time as a quarter note.
Why Subdivide?
OK, all of this note equivalency is really nice, but how is it useful? The answer is that this substitution can be used to help you learn rhythms accurately.
Believe it or not, most rhythmic inaccuracies occur on the long notes, not the short ones. Why? Well, because we don’t like to just sit on a note for a long time. We get bored. We get tired. We think that surely this note should be finished by now. We just get impatient and don’t count the longer notes for their full value.
Subdivision allows us to substitute shorter notes (which we are better at counting) in place of the longer notes (which we tend not to count very accurately).
That is a big deal because it allows us to count and hear rhythms when we are practicing much more accurately.
Subdivision can also be used to break down complex rhythms into something that is more easily understood.
Let’s go through some examples of how to do this.
Long Notes
Suppose we want to subdivide the following melody – how would we do it?
Well, the first rule of subdivision is that you should only subdivide to the smallest note that you have in the piece (or section that you are working on). The shortest note in this melody is a quarter note, so there is no need to subdivide at the eighth or sixteenth note.
For this melody, we will subdivide by substituting the correct number of quarter notes for each note that is longer than a quarter note. When we subdivide, we play this:
Practicing with this subdivision allows you to hear exactly how long each 2 beat and 3 beat note sounds. Once you are secure with playing this melody subdivided, then you can return to playing the original melody, but think the subdivided quarter notes so that the long notes retain their full value.
Complex Rhythm
Subdivision can also help you figure out complex rhythms. Let’s change our original melody to add some dotted values.
This melody now has eighth notes, which means that we will replace every note that is larger than an eighth note with the number of eighth notes that fit into it. Here is the result.
Though the dotted quarter notes made the rhythm more complex, we can figure out that every dotted quarter note receives the same amount of time as 3 eighth notes. This substitution makes it easier to figure out when to move to the note after the dotted quarter.