Acoustic measurement of periodic noise generation in a hydrodynamical vocal fold model

During phonation of voiced sounds periodic noise is generat ed due to the repeated evolution of shear layer vortices and turbulence downstream the glottis. In healthy persons, this noise sound integrates with the harmonic signal and forms a natural voice. In patients with v oice disorders the amount of noise is often increased and contributes to the symptom of hoarseness. For experimental investigation of the noise generation process a 3:1 up-scaled model of mechanically dr iven vocal folds and the vocal tract has been built in a water channel. The periodic modulation of the flow i s achieved by rotating cylinders of variable cross-section which allows to simulate the effect of voice d isorders such as bi-phonation or an unilateral palsy. The part of the project presented herein deals with th e direct acoustic measurement of the harmonic and non-harmonic components of the sound field to compare the acoustic output of this model to the voice components measured in humans during phonation. The set-up for acquisition of these acoustic signals is described and first results are presented.