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. Infinitesimal The ideal time span of mathematical durations such as the infinitely brief delta functions." Trevor Wishart English composer Trevor Wishart derives his own version of 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. Denis Smalley Denis Smalley, inspired by Schaeffer's theories, developed 'spectromorphology’ (Smalley, 1997) as tool for analysing sound materials, 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