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In electronic music theory and electronic composition theory a sound object (coined by Pierre Schaeffer)1 corresponds with a primary unit of music such that could be played on an instrument or sung by a vocalist. A sound object specifically refers to recorded sound rather than music written using manuscript or a score. More precisely, in his book Traité des objets musicaux Schaeffer considers the sound object in these terms:
This unit of sound [sound object] is the equivalent to a unit of breath or articulation, a unit of instrumental gesture. The sound object is therefore an acoustic action and intention of listening.
Schaeffer went through an evolution of thought regarding his work with recorded material/ sound objects as music. But he came to believe that the sound object should be free from its sonic origin (its sound source or source bonding) so that its source could not be identified. This type of sound object forms part of what Schaeffer called acousmatic music, which involves a reduced, or concentrated listening.
One of Schaeffer's primary aims in his treatise1 is to re-define the music object in the light of the new technology of recording. As a key part of this re-definition he feels it necessary to describe, what he claims, is the empirical function/s of listening. Schaeffer's terminology is confused and confusing in this aspect of his theory as he uses the terms: listening, hearing, perceiving aurally and understanding under the sub-heading 'listening'. So one needs to have a firm grasp of his descriptions and differentiations of meaning so as to avoid being confused by his prodigal writing style. Schaeffer's four functions of the "What Can be Heard." (Schaeffer, P., 1995, pp. 74-79) are as follows:
These are then extrapolated into "Four Listening Modes" which Schaeffer considers scientific, saying (Schaeffer, P., 1995, pp. 80): 'To give a quite empirical description of "what happens" when we listen, we will make a sort of summary of the various forms of activity of the ear.'. These modes of listening then lead to the acousmatic situation, as Schaeffer describes it. Schaeffer's acousmatic situation is focussed on the subjective "listening itself which becomes the phenomena under study" rather than the sound object's source.
Schaeffer's ideas, it is speculated, are derived or modelled on the philosophy on Phenomenology, as such, his theory is seemingly given some kind of weight, or legitimacy. Nevertheless, it's difficult to ascertain the impact of his influence, but Brian Kane, in his book Sound Unseen says:
In explicating and clarifying his theory of the sound object, Schaeffer introduced the concept of the acousmatic. "The sound object," Schaffer tersely states, "is never revealed clearly except in the acousmatic experience." In what follows, I try to show why this is indeed the case. To do so, I will explicate Schaeffer's mature theory of acousmatic experience, the sound object, and reduced listening (écoute réduite) as presented in the Traité des objets musicaux. His theory is cast in explicitly phenomenological terms, and I argue that Schaeffer's phenomenology is much closer to Husserl than it is to Schaeffer's French contemporary, Maurice Merleau-Ponty. For without a good understanding of the Husserlian preoccupations of Schaeffer's work, one cannot adequately characterize the relationship between acousmatic experience, the sound object, and reduced listening. Once those various parts of Schaeffer's mature theory have been distinctly separated, the theory and practice of acousmatic listening--the real focus of interest in this book--can begin to be addressed.
A less elucidated or perhaps looser definition of the term sound object considers all possible types of sound within stipulated temporalities, as developed by Curtis Roads in his book Microsound 5 (2001) in which he says:
1. Infinite The ideal time span of mathematical durations such as the infinite sine waves of classical Fourier analysis.
2. Supra A time scale beyond that of an individual composition and extending into months, years, decades, and centuries.
3. Macro The time scale of overall musical architecture or form, measured in minutes or hours, or in extreme cases, days.
4. Meso Divisions of form. Groupings of sound objects into hierarchies of phrase structures of various sizes, measured in minutes or seconds.
5. Sound object A basic unit of musical structure, generalizing the traditional concept of note to include complex and mutating sound events on a time scale ranging from a fraction of a second to several seconds.
6. Micro Sound particles on a time scale that extends down to the threshold of auditory perception (measured in thousandths of a second or milli-seconds).
7. Sample The atomic level of digital audio systems: individual binary samples or numerical amplitude values, one following another at a fixed time interval. The period between samples is measured in millionths of a second (microseconds).
8. Subsample Fluctuations on a time scale too brief to be properly recorded or perceived, measured in billionths of a second (nanoseconds) or less.
9. InfinitesimalThe ideal time span of mathematical durations such as the infinitely brief delta functions.
Roads therefore places the sound object in a seemingly all encompassing temporal frame, whereby it may be considered one of nine scales of time. English composer Trevor Wishart derives his own version of the sound object from Schaeffer's but unlike Schaeffer, Wishart favours a materialist or physicalist notion, saying:
Given that we have established a coherent aural image of a real acoustic space, we may then begin to position sound-objects within the space. Imagine for a moment that we have established the acoustic space of a forest (width represented by the spread across a pair of stereo speakers, depth represented by decreasing amplitude and high-frequency components and increasing reverberation) then position the sounds of various birds and animals within this space.
Another post-Schaefferian theory about sound objects is by Denis Smalley who has devised, what he describes as, 'spectromorphology', (Smalley, 1997) a tool for analysing, and shaping sound objects, he states:
I have developed the concepts and terminology of spectromorphologyas tools for describing and analysing listening experience... A spectromorphological approach sets out spectral and morphological models and processes, and provides a framework for understanding structural relations and behaviours as experienced in the temporal flux of the music.
An important aspect of spectromorphology is, what Smalley calls 'source bonding', which he describes as the duality of any given listening situation. According to Smalley, therefore, sound objects have an extrinsic nature if its source bonding remains intact, but if not, it has a sonic characteristic that is intrinsic in nature. The condition in which a sound object has an intrinsic or extrinsic source bonding depends on the experiences of the listener.
1. Note: Schaeffer's text translated here from French by S. Constantinou. Original text: 'Cette unité serait, dans le parle, une unité de respiration ou d'articulation: en musique, l'unité de geste instrumental. L'objet sonore est a la rencoutre d'une action acoustique et d'une intention d'ecoute.' See reference  above. See Constantinou, S (2015) Processes of creative patterning : a compositional approach. PhD Thesis.
Constantinou, S (2015) Processes of creative patterning : a compositional approach. PhD Thesis. https://ethos.bl.uk/OrderDetails.do;jsessionid=D38126F6CC9443F07B78636D63E7F84E?uin=uk.bl.ethos.679793
Schaeffer, Pierre (2012). In Search of a Concrete Music. Translated by North, Christine; Dack, John. London: University of California. ISBN 978-0-520-26573-8. OCLC 788263789.