Jan. 10, 2017
Augmentation / Diminution
Expansion and contraction.
It's an integral part of the known universe (photo).
Stars expand late in their lives, then explode when their cores collapse; even in the living world, every breath we take to stay alive involves these 2 principles; they're creative tools as well, which can be used to help develop new material for and breathe additional life into musical composition.
Augmentation refers to the delivery of a moving melodic line in consistently slower note values, usually by assigning a double value to each and every note in the melodic line, doubling its length (16th notes become 8th notes, 8th notes become quarter notes, quarter notes become half notes, half notes become whole notes, etc.).
The opposite process may also be applied; diminution refers to the delivery of the moving melodic line in consistently quicker notes, where each and every note in the melodic line is given typically only half its value (whole notes become half notes, half notes become quarter notes, quarter notes become 8th notes, 8th notes become 16 notes, etc.).
Certain types of melodic lines are more conducive to this kind of treatment, but not every line lends itself to it, thus, we don't find this kind of stretching or compression in every musical work we happen to run across.
It's good however, when we're writing our own music, to keep these 2 tools in mind in case we want to try using them for development of new compositional material.
They take their place among several other time-honored compositional tools that can be applied to virtually any style of music.