Tools for Sound Processing
151
MSP
Pure Data
pd
digital signal processors
sion produced by Cycling '74 and maintained by Dave Zicarelli
extension to Max, written by Zicarelli, is MSP which features real-time signal
processing objects on Apple PowerMacs (i.e. on general-purpose RISC architec-
tures). Another interesting path is being currently followed by Miller Puckette
himself who is the principal author of Pure Data (pd) [71], an open-source public
domain counterpart of Max which handles MIDI, audio and graphics (extensions
by Mark Danks
). pd is developed keeping the actual processing and its graph-
ical display as two cooperating separate processes, thus enhancing portability
and easily modeling its processing priorities (sound first, graphics later) on the
underlying operating system thread/task switching capabilities. pd is currently
a very early-stage work-in-progress but it already features most of the graphic
objects found in the experimental version of Max plus several audio signal pro-
cessing objects. Its tcl/tk graphical interface makes its porting extremely easy
(virtually "no porting at all")
Audio Modules
Control Path
Audio Path
Figure 4: A Pd screen shot
B.3.1
Examples in ARES/MARS and pd
While the use of systems that are based on specialized digital signal processors is
fading out in the music and sound communities, those kinds of chips still play a
crucial role in communication and embedded systems. In general, wherever one
needs signal processing capabilities at a very low cost, digital signal processors
come into play, with their corollary of peculiar assembly language and parallel
datapaths. For this reason, it is useful to look at the ARES/MARS workstation
15
16
17
Pure
Data
currently
runs
on
Silicon
Graphics
workstations,
on
Linux