Sound In A Nutshell: Granular Synthesis

Granular synthesis might be thought of as a recent development in sound synthesis, but it can be seen as a reflection of ideas about the nature of sound. It is only since the advent of computer and sound recording technology that it has been easy to apply this idea. Granular synthesis is based on a certain notion of what sound is, in particular, the human perception or cognition of sound. In order to be able to better understand granular synthesis, one must be able to see how the theory of sound perception was developed.

Isaac Beeckman was from the Netherlands and lived from 1588 until 1637. He was a scientist who had received no formal training and was never published during his lifetime. However he was prolific in his scientific endeavours, which also included investigations into sound. (Cohen 1984: 116-118)

Beeckman's studies in sound led him to the belief that sound is produced by a vibrating source. He stated that the vibrating causes corpuscles to be cut into the air. Beeckman never calls the corpuscles atoms, although he was a believer of an atomic theory in which everything is made up of discrete particles. He conducted an experiment that is identical to one performed by Galileo in 1638, one year after Beeckman's death.¹ Beeckman showed that rubbing the rim of a glass filled with water caused globules to form in the water and the air where the glass was being rubbed. These globules or sound particles he observed were actually standing waves within the glass, but observing the results of this experiment it is easy to see how they can be seen as particles. About a century before but unbeknown to Beeckman, Leonardo da Vinci theorised that sound travelled in waves. Galileo, Mersenne, Boyle and Newton studied this theory intensely during the 1600's. Their findings became known as the wave theory. The wave theory can be seen visually by placing a struck tuning fork, into water and examining the waves that are formed. The waves travel through the air in the same fashion. However Beeckman rejected any possibility of a wave theory. Whilst rejecting this idea Beeckman did believe in sound being transmitted through a process of expanding and contracting of particle density through the air. This can be explained as part of the wave theory, but not in the context to which Beeckman places it. (Cohen 1984: 121-123)

Whilst Beeckman is not wholly correct in all of his assumptions, he does make some very useful observations. The most important is how the globules are composed and how they function. Essentially the globules are a grain of sonic data. They contain corpuscles of sound. Beeckman also noticed that they are not necessarily continuous. During certain phases the density would vary, fewer globules would be dispersed. Even though the corpuscular theory became a part of the study on light with the insight of Newton, it was all but forgotten in terms of sound.

In the 17th century Antonie van Leeuwenhoek developed high-powered lenses which when used in his microscope was able to magnify up to 200 times without distorting the image (Taylor et al 1983: 166). Direct observation through the microscope showed that

a drop of pond water was a teeming mass of life suggestive of a crowded city (Wiener 1964: 540).

This discovery introduced a whole new world to our own world, and led people to believe there must be many things too small to see. This was the beginning of change in the perception of the world. It led to question about how small objects can be. This discovery led to many discoveries in medicine, and eventually to light, matter, and the atomic theory.

In 1900 the study of quantum Mechanics began. Max Planck argued that light is not continuous, it has a granular texture. This theory was more easily accepted due to the widespread acceptance of the atomic theory. Einstein carried on Planck's work. He showed that light is quantised, it carries specific quantities of energy. These packets of energy became known as quanta, the light particles within as photons. One man in particular, Norbert Wiener, pointed out the relationship between his quantum physics studies and the characteristics of sound.

1 The experiment conducted by Galileo was designed to prove a different point. His experiment was used to show how sound travels in waves. He filled a glass with water and rubbed his wet finger across the top so that the glass would resonate. The resonance causes waves to form in the water. Galileo used this as proof of the wave motion of sound.