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This composition was synthesized with physical modelling of mass vibrations
(difference equation resonator array). The sound-producing objects were
modelled as consisting of parts that each have a spring constant and a mass.
However, to make the model more realistic, the spring constants are mutually
modulated by the neighbour part vibrations (tension change under spring length
variations when the parts are pushing or pulling each other).
Listen Fether lyre (2M - 2:06).
For curiosity, below sound material of the piece (before they were mixed together).
Please, note that some of the material go into chaotic noise. [However parts of the
material were used in the composition because of their unique fascination!]
Listen to the sound material of the piece:
Listening Score / Performance Score
Here a listening score (sheet music) in PDF format FetherLyre_PDF (1.5M - Adobe Acrobat Document); and also in Coda Notation File format FetherLyre_MUS.zip (60k - Finale2004 score zipped) for your convenience (those of you having Finale 2004 or higher, I mean).
The original purpose of the score, for the composer, was to make a draft for an
electro-acoustic composition - even though the sound would be generated by a
separate computer music synthesis system
One day, perhaps, somebody might even want to use the score as a performance score for human player(s), (with or without optional live electronics), in a consert?
Music Synthesis Environment
The Music Synthesis System for this piece was a C++ program (MAL-d)
written by the composer.
The acronym MAL-d stands for Modular Audio Laboratory (development
environment), and the system was primarily built for evaluating
the feasibility of use of difference equation resonators for audio signal
generation. (For basics about digital signal processing, see e.g.
.) The advantage of a difference equation resonator
is small memory consumption, but with the disadvantages of need for a separate
resonator element for each partial (harmonic or non-harmonic) plus high tendency
toward instability (see e.g. ). The difference
equation approach is one way of doing so-called physical modelling.
The additional benefit of physical modelling in general is that
it is easier to produce sounds that are more lively resembling real sounds (compared
to the "dead-and-dull" sound of simple wave table synthesis). So, one
mandatory requirement for the system was ability to apply frequency modulation (FM)
to individual resonator elements, for simulating variations in the resulting
(Note: Another branch of physical modelling, Digital Waveguides
(), might achieve quite similar results when applying
variable filters in the feedback path(s).)
At a late phase of the project, also an additional feature was added for ability to
provide input events in text file (much like the score file format in the Csound
language ), though that was not an original intention
(nor a requirement either).
As an example of the MAL-d event file format, here is a file
from the Fether lyre composition project.
Here is also one article draft LyrePaperDraft_PDF,
written by me (unpublished - you are allowed to refer to the general ideas
presented in the draft but direct quotes are prohibited), concerning the
composition project and the used environment.
 Spjut, E. : An Introduction to Signal Processing with Csound;
in The Csound Book, edited by Boulanger, R. - The MIT Press, 2000.