Barry Truax – Riverrun (1986)

Riverrun creates a sound environment in which stasis and flux, solidity and movement co-exist in a dynamic balance. The corresponding metaphor is that of a river, always moving yet seemingly permanent. From the smallest rivulet to the fullest force of its mass, a river is formed from a collection of countless droplets and sources. So too with the sound in this composition which bases itself on the smallest possible 'unit' of sound in order to create larger textures and masses. The title is the first word in James Joyce's Finnegan's Wake.

Riverrun is entirely realized with the method of sound production known as granular synthesis. With this method small units or 'grains' of sound are produced, usually with very high densities (100-2000 grains/sec), with each grain having a separately defined frequency and duration. When the grains all have similar parameters, the result is a pitched and amplitude modulated sound, but when random variation is allowed in a parameter, a broad-band noise component is introduced.

All sounds in this piece were generated with real-time synthesis by the DMX-1000 Digital Signal Processor, up to a maximum density of 2375 grains/second. However, in many cases, lesser densities were also used since often the progression from isolated sounds or a rapid sequence of events to a fused texture is the most interesting feature of the synthesis method. All layers were multi-tracked with four simultaneous stereo versions and later up to 32 such tracks were mixed. Considerable use was made of ramps applied to the synthesis variables; that is, certain parameters were made to change over time at a specific rate, sometimes with several parameters simultaneously ramped at different rates. Therefore, all sound in the piece is in a constant state of flux, much like environmental sound generally and water sound in particular.

Video created with Sonic Visualizer and vokoscreen on an openSUSE 13.2 Linux System.