Microsound

A microsound is a sound that is too short to be heard on its own. It can last up to ca. 1/10 of a second. Microsounds, when heard together, can create fascinating and sometimes very dense sound complexes. Microsounds can be generated electronically or use samples as their base material.

Micro- to Macro- Sounds

When we bring micro-sounds together we create macro-sounds, larger structures of sound. These macro-sounds can themselves be built into larger structures.

Building macro-sounds in this way, from individual grains upwards, gives the composer greater control over the final outcome. The process is greatly helped by computer and electronic technology.

Composition Tip

The most important processes for this music are:

• Additive and Subtractive Synthesis
• Filters
• Granular Synthesis

Grains of Sound

Imagine the grains of sand on a beach. Each of them is very small, but together they can form sand castles and even mighty sand dunes.

Grains of sound are exactly the same. They are tiny particles of sound that, when combined together, can create fantastic new shapes and structures.

It’s often difficult for us to hear individual grains on their own because they are so small.

Masses of Sound

There are two main types of sound masses:

• Fused blocks of frequencies – created by very closely packed pitches of sound.
• Cloud textures – made from a mass of individual grains which swarm and flow together.

In both cases, the composer creates subtle transformations by altering the balance within the sounds over time.

Blocks of Sound

Within blocks of sound, the composer will subtly add or subtract pitches from within the sound mass.

Listening

Examples of such works include: Györgi Ligeti’s Atmosphères or his piece Volumina.

Cloud Textures

Clouds of sound are structured differently. These take the form of more fluid masses of sound, in which the individual grains of sounds flock and swarm, each flowing freely but within a certain trajectory.

Listening

Examples of such works include Xenakis’ piece Concret PH or Bernard Parmégiani’s De Natura Sonorum .

In these works, there may be many individual sound clouds which merge together or divide from one another.

The properties of swarming clouds of sound allow them to merge seamlessly together with a simple cross fade.

Beyond the Limits of Our Hearing

When sounds are shorter than 1/10th of a second (10ms), we can no longer hear them as individual sounds.

These tiny chunks of sound are beyond the limits of our hearing. So we don’t hear them begin or end.

Fact

Threshold is a term used to describe the limits of our hearing. If a group of sounds are shorter than our time threshold for hearing, we will not hear them individually.

The same is true for sounds that are very close together in pitch. Beyond the pitch threshold, we are unable to hear individual pitches.

This property allows us to merge sounds together in the construction of seamless masses of sound.