Augmentation & Diminution

Augmentation & Diminution

Augmentation and Diminution are rhythmic devices in music. This means that to use them is to change the rhythms somehow.

Augmentation

Simply put;

If you make each note in a melody last twice as long as it originally lasted, it will sound twice as slow.
This process is called Augmentation.

Here is an example - our good friend Twinkle Twinkle Little Star, written in G Major here.

Count the bars - the "Theme" is the original, it lasts 8 bars.
The Augmented version is made up of notes that last double the length of time as the original. It ends up with double the amount of bars. Therefore it lasts 16 bars.

Does this matter to you?
Yes, a bit. But not as much as recognising the effect in a piece of music.

If you hear a melody played in the music and then hear it repeated but it sounds twice as slow, then it has been Augmented.

Be aware: The use of the word "Augmented" here is in relation to the note value, and has nothing to do with intervals. In your study of the Harmonic Minor scale you will see the word "Augmented" applied to the interval between the 6th and 7th degree of the scale (Augmented 2nd). This is not what the stand-alone SQA concept of "Augmentation" refers to, don't get confused!

Diminution

Simply put;

If you make a melody last half as long as it originally lasted, it has been Diminished by process of [Rhythmic] Diminution.

The reason I have used all that flowery language there is to point out to you that it is NOT the same as a Diminished chord, or a diminished interval. Similarly to Augmentation, these concepts refer to specific functions in different areas of music. What you need to do is associate Diminution with the note values and not the melodic/harmonic intervals.

This process is purely rhythmic - you take the original note value and decrease it, usually by half.
This is diminution.

See our good pal Twinkle Twinkle here again, diminished by half the value of the notes. It's the process used in augmentation, but in reverse.





The resulting effect:

The repetition of a melody at twice the speed - it causes the tune to sound faster.

Diminution in Orchestral Music:

This piece is from the Romantic era but was incredibly progressive. The processes of Augmentation and Diminution existed outside of the 20th Century, they are just taught here as a matter of convenience, so don't think a piece must be from the 20th century if it uses either of these techniques!
Here I have pointed out an example of Diminution in the "Dies Irae" section of this piece of music. You hear the Dies Irae theme first in the Tuba line, then Diminished again, straight afterwards in the Horn and Trombone sections.

Look at the excerpt first and follow the instructions in red using the video below.