Nonlinear propagation of multitone one-dimensional waves. Application to sound systems modeling and analysis

Abstract

Multitone stimulus is used in identification of weakly nonlinear systems and for assessment of nonlinearity in sound and broadcasting equipment. Multitones’ spectral and statistical characteristics resemble those of the musical signals; the nonlinear response to multitone stimulus yields more versatile information about nonlinearity than conventional measurements of harmonic and two-tone intermodulation distortion. Earlier work has demonstrated that strong harmonic and intermodulation distortions accompany the propagation of waves radiated by large horn arrays. In this current work, the models of propagation of multitone waves are developed. The modeling considers propagation of multitone one-dimensional waves. The modeling is based on numerical solution of implicit equations describing distorted one-dimensional waveforms. A nonlinear model of multitone waves propagating within a horn is developed. The model considers linear propagation of the fundamental tones with reflections from the mouth and the nonlinear, reflection-free propagation of distortion products. Further research may include radiation of multitone waves by a complex source and substitution of multitone stimulus by a musical signal to provide listening tests and auralization of propagation nonlinearity. The data obtained from modeling may be used to build Volterra models of nonlinear propagation. These models might lead to signal processing solutions to minimize distortion in propagating waves.