programming with max/msp - Virtual Sound

2.1
234
Practice
Paragraph 2.1 - Fixed spectrum additive synthesis
As we learned in Section IA.10 of Interlude A, we can create a list of numbers
by using either a message box or a multislider. The first technique is immediately
obvious in this patch: desired amplitudes are grouped into lists within
message boxes, and then dispatched to the 10 multipliers by using a send object
([s partials]). The corresponding receive object is connected to an unpack
object that takes care of distributing single values to appropriate multipliers (as
seen in Figure 2.1b).
Fig. 2.1b The unpack object breaking a list into single elements
Amplitude lists might also, however, be created using a multislider. Create
one now in the lower right of the patch, and configure it using the Inspector
to have 10 sliders, each ranging from 0 to 1. This multislider will need to
be connected to a send object with the argument “partials”. It’s also possible
to manipulate the float number boxes connected to the right inlet of the signal
multipliers in order to set different amplitudes, and then save the result by using
the preset object on the left (by shift-clicking on the small dots).
The component signals in the patch, after being rescaled by their individual
amplitude multipliers, are routed to a final multiplication object in the signal
path that reduces the overall amplitude of the summed signal to 1/10th of its
original strength. We know that any two or more signals that enter a single
inlet are summed. So in the case of 10 oscillators, if all of the components have
the maximum amplitude of 1, the resulting summed waveform would have an
amplitude of 10. This multiplier, therefore, serves to return the absolute value
of the signal to a value between 0 and 1, thus avoiding distortion. 1
The amplitude multislider must dispatch data continuously, since we
would like variations to be sent out as they are made, even while the value of
a slider is being changed. By default, however, multislider updates the list
of values that it outputs only when the mouse is released, at the end of an edit.
To configure the object to produce continuous updates, you must call up the
Inspector for the object, and after selecting the Style tab, check the box that
enables “Continuous Data Output when Mousing”.
Using this patch, create various spectral profiles, saving them as presets and
changing between them to compare the differences in timbre made by lower,
middle, and upper components, as we covered in the theory chapter.
1 For a discussion of distortion due to excessive amplitude see Section 1.2 of Chapter 1T.
from “Electronic Music and Sound Design” Vol. 1 by Alessandro Cipriani and Maurizio Giri
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