Observable effects of sound source-tract coupling

EZEQUIEL M. ARNEODO; YONATAN SANZ PERL; GABRIEL B. MINDLIN

Rio de Janeiro

Congreso; 18 International Congress of Sound and Vibration - ICSV 18; 2011

International Institute of Acoustics and Vibration

Birdsong is a complex phenomenon, generated by a nonlinear vocal device capable of displaying complex solutions even under simplephysiological motor commands. The variety of morphologies among bird species makes it an idealmodel to study phenomena associated to the production of complex vocalizations. In the way of understanding how these varied, complex sounds are produced in the vocal organ,little has been learned about the acoustic effects introduced by the interaction between a sound source and a vocal tract. Inspired in the sound production mechanisms of songbirds, we propose a mathematical model of a vocal organ, in which a simple sound source interacts with a tract, leading to a delay differential equation.We explore this system numerically, focusing on the regions in parameter space where the frequencies of the oscillatory solutions of the uncoupled source are close to the resonances of the tract.In this way, we search for effects introduced by the source-tract coupling which are observable in the acoustic features of the vocalizations produced in the system. By studying the system analytically, we put these effects in the context of the nonlinear dynamics of the model.