Augmentation & Contrary Motion

This follows on from the Augmentation post, as it may interest you to see two concepts used as compositional techniques to grow a piece of contrapuntal music.


As you will know from your listening journey until now, most composers appeared to be pretty lazy... or obsessive.

Either way, they know how to spin a long life out of not much material!

Take this piece by J.S. Bach.

If you look more closely at this piece, you will see that Bach has worked with a simple melody and stretched it out to create this piece of music.

He has followed these steps:

1. Write a melody that you quite like. (His is 23 notes).
2. Turn that melody upside-down (a process called inversion - which you will know from your work on Serialism)
3. Wait a little bit for the first voice to produce the melody you liked in the first place
4. Let the second voice join in, playing the inversion of your melody.

Then he has added step 5: Augmentation.

Look at the first theme:

Count the intervals between each note, and you'll notice that when the bass clef part enters (as it is a staggered entry we call this a Canon, entering later with the same material!) although it is going down instead of up in pitch, it's retaining the same interval distance between each note.

The notes are colour coded so you can see the relationship more clearly.

Here's the colour representation of the theme so you can check up where it matches:

The last thing Bach has done with this first few lines of music, is he has used Augmentation to create his contrapuntal music from that one set of 23 notes. Look at the note values.

For example: The pink and orange starting notes are quavers.

In the inversion of the motif, they are now crotchets.

He has taken the note values and doubled them.

This process is called Augmentation

Compositional Task:

Write a short phrase and turn it into a Canon using Augmentation and Inversion. The result will be a two-voice piece of music that is contrapuntal in nature, the two voices move in contrary motion, and the compositional techniques you used were inversion and augmentation.

If it sparks your creativity, go on and build on it. Perhaps add a third canon entry in another voice? Could you use Diminution to add interest? Does it work?