A Symmetrical Two-mass Vocal-fold Model Coupled to Vocal Tract and Trachea, with Application to Prosthesis Design a Symmetrical Two-mass Vocal-fold Model Nr. of Gures: 12 1 Institute for Perception Research (ipo) 2

We propose a two-mass model for the vocal folds. The aerodynamic force resulting from the air ow through the glottis is distributed over both masses, as opposed to some earlier models in which the force is allocated to the upstream mass only. This allows the choice of a symmetrical vocal-fold structure, with two identical mass-spring systems. The number of mechanical parameters is thus reduced. Their choice is inspired upon analysis of the eigenmodes of the actual vocal folds. The new aerodynamic force distribution allows acoustic feedback from vocal tract and trachea to be considered; sub-and supra-glottal systems are modelled as transmission lines. The ow model includes a simple ow-separation description. Parameter values are based on physiological measurements and calculations reported in literature. However, as in any vocal-fold model it is inevitable that parameters also partly make up for simpliications in the model. The model predictions are shown to compare well to in-vivo experimental data from literature concerning acoustic feedback. The two-mass model is applied to study the eeect of size and position of a vocal-fold prosthesis on its performance. We indicate how the model should be modiied to provide order-of-magnitude estimates of the eeect of ow inertia and uid viscosity. The described improvement of the ow model is not of predictive value within the framework of the simpliied mechanical model we propose.