a Digital Instrument for Additive Sound Synthesis
consists of a
M4C type instrument and a score editor both written in C.
DIASS was designed by Sever Tipei and Christopher Kriese and
the initial code was written by Christopher Kriese in 1991-92. Under
the supervision of Sever Tipei, during 1994-96 David Ralley expanded
the capabilities of the instrument and, together with Cheryl Herndon,
added the loudness routines which allow the user to
specify the perceived loudness of a sound event. A team
including Dave Blumenthal, Mario Lauria, Thomas Lawrence, and
Scott Pakin modified M4C and wrote a parallel version using
a message passing library. Their work was done as a class project
for Sever Tipei's seminar
Musical Applications On Supercomputers
offered in Spring 1995. During spring 1996 Dave Blumenthal and
Max Levchin developed M4CAVE an OpenGL program which creates
images in a 3D virtual environment
(CAVE), from the same "score" that produces the sounds.
Arun Chandra worked on improving the code during 1996-1997. Presently
Mike Piacenza, Bill Whitehouse, and a group of Musical Applications
On Supercomputers seminar are working on restructuring the code and
at translating it into C++. Prof. Sang Lyul Min from Seoul
National University has contributed substantially to the
optimization of the parallel code (DIASS_M4C).
Senior Mathematician at Argonne National Laboratory, has been contributing
to the restructuring of the program and has been supervising the project
together with Sever Tipei since 1994.
Description of the instrument:
- DIASS can handle an arbitrary number of
consecutive and/or simultaneous sounds of up to 65 partials each.
Every partial can be independently controlled through static
parameters (which do not vary during its duration) and through dynamic
parameters (which may vary during the life of the partial).
- There are 12 static and 13 dynamic parameters. The static
The dymanic parameters include:
- start time
- reverberation characteristics such as
- hall size
- duration of the reverberation.
- phase, etc.
- magnitude and rate of:
- amplitude modulation
- frequency modulation
- transients of amplitude
- transients of frequency
- mix between direct and reverberated sound, etc.
- A number of macros apply certain operations to all
partials making up a sound. They include:
- tuning of a sound's partials according to desired ratios
- dynamic tuning and detuning of partials during the
duration of a sound
- scaling of each partial's amplitude as a percentage
of the fundamental's amplitude
- enhancing or dampening of certain frequency bands
similar to the effect the body of an acoustic instrument
has on the resulting sound
- perceived loudness of a sound, etc.
- A unique feature of DIASS is the scaling of amplitudes
according to the desired perceived loudness of the
resulting sound event. The Fletcher-Munson curves are used to
determine the amplitude necessary to produce a certain
perceived loudness in phons. They are further
adjusted taking into consideration the critical bands whithin which
they might fall (see references below).
- The anticlip option insures (before the samples are
computed) that there will be no "clipping" in the sound file.
If one or more samples exceed the maximum amplitude allowed,
the entire piece will be scaled accordingly. Except that, in
stead of lowering the amplitude across the board, each different
combination of simultaneous sounds is evaluated by the
loudness routines and each partial is re-scaled according
to the Fletcher-Munson curves and to their position within critical
bands. Practically, this results in the fact that works with a
wide dynamic range can be produced in one run of the program
without resorting to "post-production" digital or to analog
- There are two versions of the score editor, diassin
and fast, and two versions of the M4C
instrument, sequential and parallel.
- diassin or the slow version of the editor
allows the user to experiment with creating new sounds through
a menu or through a Graphic User Interface (GUI) presently
under construction. The process is slow due to the large
number of options available to the user.
- The fast version of the editor is recommended
in production mode or when using the output of a computer-assisted
composition program. A script provides the answers to the
questions posed by the menu of the slow version.
- As the name indicates, the sequential version
of the M4C instrument requires only one processor.
- The parallel version of the instrument uses
MPI a message passing library to divide the
computations between a number of nodes. All nodes except two
compute one sound at a time each until the piece is finished. One of
the remaining nodes has the task of distributing the work load
and the last one mixes together the computed sounds as they arrive.
Works produced with DIASS:
- Sever Tipei
- AGA MATTER for piano and computer generated tape, 1992.
- RICE MATTERS for computer generated tape, 1993.
- CURSES for solo male voice, backup group and computer
generated tape (some of the sounds), 1996.
- ANL-folds manifold compositions
for computer generated tape, 1996 -
- Sonic Residues, for computer generated tape; 50 variants
were performed on December 21, 1997 at the
Linden Gallery, in Melbourne, Australia.
- BERLIN-folds #1, #2, for computer-generated tape (1998)
- A.A.-folds, for computer generated tape, an installation
at Int'l Computer Music Conference 1998, Ann Arbor, Michigan.
- Christopher Kriese and Sever Tipei - A Compositional
Approach to Additive Synthesis on Supercomputers, Proc.
of the 1992 Int'l Computer Music Conf. (San Jose,
California; September 1992),
International Computer Music Association, San Francisco, CA,
1992, pp. 394-395.
- Hans Kaper, David Ralley, Juan Restrepo, and Sever Tipei -
Additive Synthesis with DIASS_M4C on Argonne National
Laboratory's IBM POWERparallel System (SP), Proc.
of the 1995 Int'l Computer Music Conference (Banff,
Canada; September 1995)
International Computer Music Association, San Francisco, CA,
1995, pp. 351-352.
- Hans Kaper, David Ralley, and Sever Tipei - Perceived
Equal Loudness of Complex Tones: a Software Implementation for
Computer Music Composition , Proc. 1996 Int'l
Conf. in Music Perception and Cognition (Montreal, Canada;
August 1996), pp.127-132.
- DIASS was also presented at the SuperComputing'95
(San Diego, California; December 1995),
SuperComputing'96 (Pittsburgh, Pennsylvania; November
SuperComputing'97 (San Jose, California, November 1997)
conferences as part of the Argonne National Laboratory
as well as at the ICAD (Palo Alto, California; November 1997)
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