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aleatory

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Aleatory/Indeterminancy/Chance Music

 

"Music whose composition and/or performance is, to a greater or lesser extent, undetermined by the composer." (Grove)

 

Introduction

 

It could be argued that all music is aleatory to more or less degrees (Wuorinen, C.; Luening, O.). A composer might prescribe the most elaborate and detailed instructions for the performance of a composition, but there will always be factors that remain variable and thus outside the control of a composer/performer. Even in the case where a composer performs their own piano composition and where they are themselves the only listener, variables exist. These could include such things as variations in acoustical properties of different rooms where the piano might be situated, tuning differences or other mechanical variances from one instrument to the next, or even simply their own human limitations and imperfections that make 'perfection' of any performance a lofty but ultimately unattainable ideal.

 

That said, the Grove definition of aleatory (aleatoric) music is meant to apply to those composers who consciously eschew traditional notions of composition and/or performance control. As such, certain historical practices of performance, such as improvised cadenzas, ossia, and ad libitum passages fall outside of the definition, as does improvisation that is idiomatic to jazz traditions and folk styles of music. It also excludes compositions such as J.S. Bach's Goldberg Variations where each variation could potentially be regarded as an independent piece.

 

History

 

The etymology of the word aleatory is traced to the Latin aleatorius (of a gambler) and alea (a dice game). Eighteenth century composers such as Mozart and Haydn wrote novelty pieces whereby simple tunes were generated in response to dice throws. Strictly speaking, these pieces aren't aleatory as such because the tunes yielded by this process still conformed to outcomes already determined by the composer. (Grove)

 

Charles Ives was perhaps the first composer to seriously explore aleatory techniques, such as annotating his scores with performance directions that were extremely open to interpretation and often unable to be realised in practice. However, as these scores weren't performed in his lifetime his influence was limited to those composers who knew him personally. Among these people was Henry Cowell.

 

Cowell's early works for piano in the 1920s called for unusual techniques such as playing the strings inside the piano and playing dense blocks of tone clusters. At the time, neither of these techniques could have been said to produce predictable timbral results and thus were aleatoric in nature. Cowell's pioneering theories of harmonic rhythm were also a seminal influence on the American avant-garde that followed him.

 

Aleatory composition, indeterminancy and chance are often cited as a reactionary outgrowth of the highly formalised and formularised processes of serialism. (Duckworth, W. et. al.) Pierre Boulez coined the term 'aleatory music' in the mid-1950s (Trenkamp, A.) but it was his older contemporary John Cage who is remembered as the perfect embodiment of the experimental attitude inherent in aleatoric techniques and so essential to the avant-garde music world that grew in his shadow.

 

John Cage

 

It is no overstatement to say that arts generally and music specifically in the second half of the twentieth century were profoundly affected by John Cage. His name has become synonymous with aleatory composition and his single-minded approach to indeterminancy and chance in composition and performance can be likened to way Bach and Beethoven exhausted the fugue and sonata forms respectively. It is also the case that Cage, unlike Bach and Beethoven whose compositions are often heard and well known, is known more for his compositional processes than the actual sound of his compositions. This is especially ironic given that Cage's aleatory methods of indeterminancy and chance were intended to obscure his processes and, by extension, his 'composer's ego'. (Darter, T.)

 

Zen & The Art of Composition

 

John Cage's whole philosophy of music and life stems from two Eastern sources that he came into contact with in the 1940s. His affinity for the Indian aesthetics as taught by Ananda K. Coomaraswamy led him to the belief that art should "imitate nature in her manner of operation" (rather than in her outward appearances). To this end, Cage's processes for composition over-rode the importance of any finished object or artifact, as was the traditionally held view in Western art and art music. Cage also found personal resonance in Hindu beliefs about perception, particuarly with regards to the age-old question, "what is music?" For Cage, every sound in existence forms a part of a musical experience. This was no more pointedly expressed than in his most notorious composition, 4'33.

 

The second and equally important cornerstone to Cage's philosophy was that of Zen Buddhism. At around the same time of his interests in Indian aesthetics, Cage attended classes on Zen given by Dr. Daisetz T. Suzuki at Columbia University. It was as a result of these that Cage was led to consider removing his ego (conscious taste and memory), thought to be the most dominant control factor that could be exerted by a composer or performer over music.

 

In order to remove as much of himself as possible from the composition process, Cage soon started to experiment with chance operations. The earliest of these experiements simply involved blocks of notation on charts but the specific order of these sounds was left to chance operations. A short time later Christian Wolff, a collegue, gave Cage a copy of the I Ching, otherwise known as the Book of Changes -- an ancient Chinese method of divination based on 64 hexagrams (similar to dice).

 

It is outside the scope of this essay to fully explain how Cage used the I Ching, but a simplified analogy can be found in Luke Rhinehart's novel, The Diceman. In it, Rhinehart surrenders all control of his destiny to throws of dice. Similarly, Cage surrendered traditionally held compositional controls such as temporal and timbral organisation to the I Ching. It is interesting to note at this point that complete control can never be entirely surrendered unless the composer completely withdraws from the process. This wasn't possible for Cage as long as all of the options he created to be randomly selected were, in fact, determined by him. Stochastic compositional methods (an outgrowth of indeterminancy and chance music) later provided further means for this withdrawal of the composer from the process however, parameters for composing and performing are still present even if obscured by the maths of their operations.

 

Examples of the results of Cage's use of I Ching in composition can be heard in the following:

 

  • Music of Changes (1951): A four-volume work for solo piano in which every sound was chosen and placed by chance operations. Listen to Excerpts
  • Concerto for Prepared Piano and Chamber Orchestra (1951)
  • Imaginery Landscape No.4 (1951): A piece for twelve radios tuned to different stations. Two players operate each radio; one controlling the volume and the other, tuning.

 

Features of Aleatory Technique

 

There are three main characteristic features, used either separately or in combinations, that can be used in aleatory composition.

 

  1. The use of random procedures in the generation of fixed compositions.
  2. The allowance of choice to the performer(s) among formal options stipulated by the composer.
  3. Methods of notation which reduce the composer’s control over the sounds in a composition.

 

 

 

Aleatory Composition in Practice

 

The following is a brief outline of the aleatoric processes used in the composition of a tune called Happenstance (Right-click to Download). The composer (Ken Taylor) shares a similar philosophical aesthetic as John Cage, though he prefers serendipitous over aleatoric, indeterminancy or chance to describe his music. A poetic definition of serendipity can be found in John Barth's novel, The Last Voyage of Somebody the Sailor:

 

"You don't plot a course for serendip but instead, you must set out in good faith for elsewhere and lose your bearings serendipitously."

 

Step One

 

An 8 note diminished scale was selected randomly from Nicholas Slominsky's Thesaurus of Scales and Melodic Patterns (scale #392: C Db Eb E F# G A Bb) with the first tetrachord repeated an octace higher to yield a total of 12 degrees of the scale.

 

Step Two

 

These tones were assigned to individual MIDI sequencer tracks and each of these looped at different cycle rates. For example, the lowest C was set to play once on beat one of a loop in 4/8 meter while the highest E played beat one of a loop that cycled in 13/8. These loop lengths were decided on a whim, though more formal chance processes could have been applied to each loop to establish cycle lengths. In either case, because of the number of variables, it was impossible to anticipate the effect of all these loops coming together.

 

Step Three

 

All of the loops were mixed down to a single MIDI track and printed out in bass clef in 4/4 time. At the stage, the aleatoric method of note generation created a piece that sounded a lot like one of Ligeti's Mechanical Piano pieces and was rich with dense tone clusers and irregular rhythms.

 

Step Four

 

An eight bar section was excerpted at random (from bar 187 of the seed file created in step three). From this, a bass line was extrapolated from the chord clusters and used to create the intro section. It is repeated several times; firstly as a solo bass line, secondly with piano in unison with it, and the final two times joined by a drum pattern written to suit the irregular rhythms. This drum cell of 16 bars was then looped throughout the composition.

 

Step Five

 

The main body of the piece consists of the seed file orchestrated across a wide timbral range. The bass was created using the extrapolation method used for the introduction. This was then duplicated twice and transposed up several octaves to be played by other instruments. Each of these duplicates was also delayed by several bars and processed with a delay effect to create further rhythmic dissonance.

 

Step Six

 

The seed file was used to create a 'piano solo' throughout the middle section. It was transposed into the middle timbral range and then reversed. Doing this created a texture that went from thin and sparse to thick and dense in a way reminiscent of a Thelonious Monk solo.

 

Step Seven

 

An overdub was finally recorded live over the arrangement to add some 'human randomness'. The sound patch used was a blend of several ethereal textures to create a subtle rhythmic pulsing. This was overdubbed in free time without any regards to the existing temporal organisation of the tune.

 

Further Listening

 

 

Related Concepts

 

 

Creativity & Aleatory Resources

 

 

References

 

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