This term refers to the manner in which the possible vertical
range of human hearing is characterised through the occupancy
and evolution of the frequency content of sound. The concept is
key to Spectromorphological theory, and the composer and writer
Denis Smalley introduces extremely detailed descriptive
termninology in "Spectromorphology: Explaining Sound-shapes".
Organised Sound Vol. 2, No. 2. Cambridge: Cambridge University
Press, 1997. It should be noted that it is difficult to separate
this concept from the perception of pitch, harmonicity, timbre,
sound quality and motion. See also:Composed Space, Discourse
within Electroacoustic Music, Frequency, Motion,
Spectromorphology, Spectrum