A passage of music where the length of the notes used are doubled, for example, where a quaver was used originally it would be replaced by a crotchet. This has the same effect as the music sounding slower although the overall pulse remains the same.
The example below illustrates how augmentation works by replacing notes from the original melody with notes of double the value.
Listen to how the tune changes around the 30 second mark.
- Diminution (H)