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In this method the user defines a hierarchy of structures to create
the sound. The hierarchy can contain recursive elements.
This structure is defined by a series of factor arrays. ``Time'' is the
factor which defines the segmentation of time into different
cells. All parameters
are developed by applying the current level factors to higher level values.
Thus, a segment of sound becomes
a multi-layer collection of cells organized in time, while a series
of parameters are active for the duration of every cell.
It is useful to explain the synthesis method with a simple example.
In this example, we will explain how the time segmentation and development
of a single parameter (frequency), is achieved.
Imagine
that we define a structure with equal time segmentation (0.5, 0.5), and
frequency factors of 1 and 2. We will assume that we want to synthesize
2 seconds of sound with an initial frequency value of 100 (the word
``initial'' does not mean that the sound is going to start with that frequency
or even have a partial at that frequency; it simply means that this is the
value with which the parameter development starts). First we divide
the time according to the time segmentation factors. Then we multiply
the initial value by the two factors and assign new values to each segment.
If we recursively apply this process to each segment, we obtain a multi-layer
series of frequency values (Table 5.1).
These values can be used for a variety of methods of synthesis of sound
(e.g. waveshaping, granular, FOF, or MIDI pitch sequences) or graphics.
Table 5.1:
Parameter development used in the synthesis method is illustrated
in this table. The time segmentation of (0.5,0.5) implies an equal binary
segmentation of time.
|
Time Segmentation |
Frequency Factor |
Segment 1 |
0.5 |
1 |
Segment 2 |
0.5 |
2 |
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Shahrokh Yadegari
2001-03-01