Klangmodellierung von Gamelaninstrumenten basierend auf exponentiell ausschwingenden Sinuskomponenten

Thesis

Modelling of Gamelan sounds based upon exponential fade out of sinusoidal components

In the present project work sounds of Gamelan instruments of the loud style are described through a simple, parameterisable signal model. The analysed instruments are derived from the group of idiophones. Idiophone sounds are specified through the shape of their extensively abrupt incipient sinusoidal vibrations with exponential fade out. These shapes represent the Eigenmodes and overtones of the particular resonance body. The analysis- and synthesis model has to treat the characteristics of all overtones separately, because this is required in the context of the project "Virtual Gamelan Graz (VGG)" [1]. The sound synthesis should combine only the signal components that have been defined relevant to human hearing and are described through a reduced number of parameters.

During the first part of the project work the consistency of the spectral components of each sound shall be elicted. In the run-up the sounds are to be filtered, which shall eliminate all masked components or components insignificant to the human ear. Ergo, the influences of outer ear, middle ear and cochlea are considered by the calculation of simultaneous spectral masking and time-varying auditory masking threshold [2]. The second part of the project work comprises the identification of all remaining frequencies with appropriate initial phase, initial amplitude, and damping coefficient through the "Frequency Zooming Autoregressive Moving Average (FZ-ARMA)" [3]. These four parameters should help resynthesise the sound of the gamelan sound.

References:

[1] Alois Sontacchi, Franz Zotter, ”Zwischenreport zum Projekt Virtual Gamelan Graz (VGG)”, IEM Report 35/06, http://iem.at/projekte/publications/iem_report/report35_06/report35_06, 2006.

[2] Frank Baumgarte, ”Ein psychophysiologisches Gehörmodell zur Nachbildung von Wahrnehmungsschwellen für die Audiocodierung”, Dissertation, Fachbereich Elektrotechnik und Informationstechnik, Universit¨at Hannover, 2000.

[3] Matti Karjalainen et al., ”AR/ARMA Analysis and Modeling of Modes in Resonant and Reverberant Systems”, 112th AES Convention, Convention Paper 5590, May 10-13 Munich, Germany, 2002.