SLIDE 6 Thomas Grill: Sound quality of textural audio: characterization, modeling and visualization Saint-Arnaud, N. (1995). Classification of sound textures. Master’s thesis, MIT Media Lab, Cambridge, MA, USA
A sound texture is like wallpaper: it can have local structure and randomness, but the characteristics of the structure and randomness must remain constant on the large scale.
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Textural sound
2.2 Working Definition
First Time Constraint: Constant Long-term Characteristics
A definition for a so~und texture could be quite wide, but we chose to restrict our working definition for many perceptual and conceptual
- reasons. First of all, there is no consensus among people as to what a
sound texture might be; and more people will accept sounds that fit a more restrictive definition. The first constraint WC! put on our definition
is that it should exhibit similar characteristics
two-second snippet of a texture should not differ significantly from another two-second snippet. To use another metaphor, one could say that any two snippets of a sound texture seem to be cut from the same rug [RIC79]. A sound texture is like wallpaper: it can have local structure and randomness, but the characteristics of the structure and randomness must remain constant on the large scale. This means that the pitch should not change like in a racing car, the rhythm should not increase or decrease, etc. This constraint also means that sounds in which the attack plays a great part (like many timbres) cannot be sound textures. A sound texture is characterized by its sustain. Figure 2.2.1 shows an interesting way of segregating sound tex- tures from other sounds, by showing how the “potential information content” increases with time. “Information” is taken here in the cog- nitive sense rather then the information theory sense. Speech or music can provide new information at any time, and their “potential information content” is shown here as a continuously increasing function
- f time. Textures, on the other hand, have constant long
term characteristics, which translates into a flattening
information
- increase. Noise (in the auditory
cognitive sense) has somewhat less information than textures.
FIGURE 2.2.1 Potential Information Content of A Sound Texture vs. Time content
speech music sound texture noise b
time
Sounds that carry a lot of meaning are usually perceived as a
- message. The semantics take the foremost position in the cognition,
downplaying the characteristics
- f the sound proper. We choose to
work with sounds which are not primarily perceived as a message.
Chapter 2 Human Perception
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