5 – Microtemporal listening dimensions: Timbre, Harmony and Pitch height69In music, differences of timbre permit the distinction of instruments,
voices and sound streams heard simultaneously, and differences between
timbral qualities can evoke spatial impressions of foreground and
background. Timbres may be heard as clearly separated simultaneous
layers, or they may merge in particular fused color qualities.
In the surrounding world, timbre is the listening dimension that enables
us to estimate the nature of sound sources and sounding objects, distin-
guish between them, recognize and identify them. The identification of
timbre answers the question, "What is it?". The simultaneous
question, "Where is it?", is answered by spatial
listening, enabling us to localize sound sources and sounding objects.
Together, timbre perception and spatial perception provide auditory
images of the variable relations between the listening mind and body and
the surrounding world.
Two kinds of auditory perception are simultaneously active in the brain.
One provides the basis for spatial discrimination, the other provides the
basis for object discrimination. Information about sounding objects and
information about spatial relations is processed simultaneously in two
parallel systems.Jean-Claude Risset provides this description of the auditory potential for
spatial orientation;The original function of hearing is not to extract the "parameters" of a
sounding signal, but rather to induce useful indications about the
environment from it. One would think that the evolution of hearing
has tended towards benefiting as much as possible from the proper-
ties of sound, which spreads at distance and winds round obstacles;
hearing plays an attentive role, it is particularly sensitive to changes,
and it has a tendency to eliminate the "background noises" from
consciousness - that is why an internal evolution, a spectral flux, is
necessary in order that a timbre be of interest. Hearing is equipped
with a well-developed mechanism permitting the evaluation of the
distance and direction of a sound source, and it possesses procedures
which help to maintain "the constancy of real things" (Koffka), just as
vision does not deduce the size of an object merely from the dimen-
sion of the image on the retina. (Risset, 1986)ng.
The Musical Timespace70The auditory potential for detecting and distinguishing "real things" in the
world is timbre perception. Timbre is the sounding equivalent of the
nature of a sound-emitting object, conveying information of its material,
size, state and the way of excitation that evokes the sound.
Gerald J. Balzano has proposed an explanation of the multivariable
characteristic qualities of timbre, referring to J.J. Gibson's "The senses
considered as perceptual systems";We get a clue from Gibson's (1966) talk of sounding things in our envi-
ronment: "The train of waves is specific to the kind of mechanical
disturbance at the source" (p. 81). I suggest that the kinds of things
we are capable of hearing that are important for timbre perception
are events like pounding, blowing, bowing, plucking, rolling, whist-
ling, screaming, and all sorts of physical processes that words can
only hint at but which are nonetheless specified in the underlying
dynamics of the signal, and therefore just as potentially "available"
to a perceiver as a Fourier spectrum. (Balzano, 1986)The Fourier spectrum is the core of the classic view of timbre, introduced
more than a hundred years ago in the psychoacoustic studies of Hermann
von Helmholtz. A Fourier spectrum is the result of a mathematical
analysis of sound, based on the theory of the French mathematician
Fourier, implying that any periodic sound vibration can be analyzed and
represented as a spectrum of pure sine wave tones.Contemporary research has demonstrated the limitations of this view
(Risset and Wessel 1982). One main reason is the fact that the attack and
temporal change of sound are just as important, or even more important
for timbre perception than the steady state spectrum. The techniques of
modern computer synthesis have permitted the investigation of the rapid
changes in the microspace of timbre.The nature of timbre is transition and multidimensionality
Timbres may be more or less complex, but no timbre is a simple pheno-
menon. Xenakis points out the limitations of the Fourier analysis;
It seems that the transient part of the sound is far more important
than the permanent part in timbre recognition and in music in
general. Now, the more the music moves toward complex sonorities
close to "noise", the more numerous and complicated the transients
become, and the more their synthesis from trigonometric functions
becomes a mountain of difficulties, even more unacceptable to a
computer than the permanent states. It is as though we wanted tong.