Russolo and Noise
Russolo's orgiastic celebration of the modern city in his Art of Noises Manifesto of 1913 (Russolo 1986) included one of the first attempts to classify sound. He wished to establish a paradigm for interpreting and using noise. His taxonomy was analogous to musical harmony. By defining categories of whispers and rumbles, Russolo situated his noises within a hierarchy. Like music in a specific key where some tones can be used more than others, Russolo's catalogue of sounds permits compositional, structural thinking.

Six Categories of noises for the Futurist Orchestra
1 - Roars, claps, falling water, driving noises, bellows
2 - Whistles, snores, snorts
3 - Whispers, mutterings rustling, grumbles, grunts, gurgles
4 - Shrill sounds, cracks, buzzings, jingles, shuffles
5 - Percussive noises using metal, wood, skin, stone, baked earth
6 - Animal and human voices; shouts, moans, screams, laughter, rattlings, sobs
(Russolo 1986)page 10

Investigation of this list offers several ways of considering the material compositionally. Human sounds (6) could be combined to create a narrative layer. Percussive sounds (5) suggest repetition and rhythm, while sounds from category four are reserved for dramatic interludes. Category one's roars, claps and bellows can heave away in the distance creating a context for gestural revelry with a foreground made from category two.

Varése and 'Organised Sound'
Russolo was not a composer but a painter. Listen to Corale (Russolo 1913) and compare this with Hyperprism 1924 (Carter, Boulez et al. 1995) Track 4

Varése was a visionary who aspired to 'music as organised sound'

"I long for instruments obedient to my thought and whim, with their contribution of a whole new world of unsuspected sounds"
Varése June 1917 quoted in (Russcol 1994)page 43

Hyperprism, features compartmentalization of sound. Sonic objects are let loose to reverberate in their own space. Sounds emerge as themselves rather than as part an emotive musical discussion lead by harmonic drama such as was exemplified in late romantic music. There is a library of sound in Hyperprism and this is what Varése allows us to hear, a sonic structure steadily and boldly articulated.

Webern and klangfarbenmelodie
While Varese was bent on moving beyond the conventional orchestra towards a controlled timbral ensemble, other composers such as Webern, a graduate of the Second Viennese School were engaged in the dissection tonality in favor of compartmentalized serialization of pitch.

Serial composition involves the composition of a series of tones, usually following the rule that no pitch in the series can be repeated until all others have been exposed. This thinking lead composers to create libraries of allowable tone rows and permutations based on the original seed. If a line of notes was taken from this library of allowable structures then the piece would maintain its harmonic integrity. A simple tone row library would involve something like the following;

Prime formats
Prime Form (P-0) C# Bb Eb E C B F# F D G Ab A
Retrograde (R-0) A Ab G D F F# B C E Eb Bb C#
Inversion (I-0) C# E B Bb D Eb Ab A C G F# F
Inverted Retrograde (IR) A Bb B E C# C G F# D Eb Ab F

Transpositions;
Retrograde Inversion (RI-0) F F# G C A Ab Eb D Bb B E C#
Retrograde Inversion (RI-4) A Bb B E C# C G F# D Eb Ab F

Webern's work stands out as a breathtaking example of serial composition. As with Varése we are permitted to hear the library in action. Consider the first movement of Opus 10, (Webern 1951) where a device known as klangfarbenmelodie articulates the pitch set.

Stockhausen?€™s Points
Beyond Webern?€™s open and unconcealed library, Stockhausen?€™s libraries were veiled by a layer of complexity but none the less, they are performed and listening for the library is one way of navigating the work.

Microsound and algorithmic(automated) library thinking

The smaller the unit of sound, the greater opportunity there is for control. Xenakis showed the possibility for granulation as a way towards creating endlessly varying textures from controlling a potentially infinite array of discrete points. This method of control is known as granulation.
See Curtis Roads Microsound for more information (Roads 2001)