Nonlinear Intermodulation of two Coherent Acoustic Progressive Waves Emitted by a Large Bandwidth Loudspeaker

The main purpose of the paper is to contribute at presenting a formalism which would be relevant for interpreting qualitatively the nonlinear harmonic distortion, and more particularly the strong intermodulation, which occur in air in the frequency range (20 Hz-20 kHz) when the vawe is propagating. For that purpose, the one-dimensional nonlinear acoustic propagation in infinite medium of two harmonic waves, at frequencies respectively equal to several Hz and several kHz, is dealt with. Despite the experimental uncertainties which result from the nature of the field emitted by the large bandwidth loudspeaker used, it can be concluded especially that intermodulation due to nonlinear effects when the acoustic wave propagates provides important non harmonic distortion in usual listening conditions.