programming with max/msp - Virtual Sound
programming with max/msp - Virtual Sound
programming with max/msp - Virtual Sound
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3.1<br />
298<br />
Theory<br />
Paragraph 3.1 - <strong>Sound</strong> sources for subtractive synthesis<br />
> Interpolated pseudo-random sample generators<br />
These generators use interpolation between each random number and the<br />
next. (See the section on linear interpolation in Chapter 2.1.) As you can<br />
see in Figure 3.4, intermediate samples, produced during the gaps between<br />
random value computations, follow line segments that move gradually<br />
from one value to the next.<br />
amplitude<br />
Fig. 3.4 Generation of pseudo-random values <strong>with</strong> linear interpolation<br />
Interpolation between one value and the next can be linear, as shown in the<br />
figure, or polynomial, implemented using polynomial functions to connect<br />
the values using curves rather than line segments. (Polynomial interpolation is<br />
shown in Figure 3.5, however, we will not attempt to explain the details here.)<br />
The kinds of polynomial interpolation most common to computer music are<br />
quadratic (which use polynomials of the second degree) and cubic (which use<br />
polynomials of the third degree). Programming languages for synthesis and<br />
signal processing usually have efficient algorithms for using these interpolations<br />
built in to their runtimes, ready for use.<br />
amplitude<br />
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time<br />
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time<br />
Fig. 3.5 Generation of pseudo-random values <strong>with</strong> polynomial interpolation<br />
from “Electronic Music and <strong>Sound</strong> Design” Vol. 1 by Alessandro Cipriani and Maurizio Giri<br />
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