Convention Paper
Modelling and Measurement of Nonlinear Intermodal Coupling in Loudspeaker Diaphragm Vibrations
AES Convention 147 · Paper 10244 · October 2019
Abstract
Accurate prediction of the nonlinear transfer response of loudspeakers in the full band is relevant to optimize the development of audio products. Small size, light, and efficient transducers require low density and thin diaphragms, which may vibrate nonlinearly even at low amplitudes impairing the sound quality. This paper proposes an extension of the existing transducer model comprising breakup modes with geometrical nonlinearities, adding the nonlinear coupling effect between the piston mode and the breakup modes responsible for large intermodulation problems. A novel measurement technique to estimate the breakup frequency modulation induced by the piston mode excursion is presented, the model is validated with measurements of harmonic and intermodulation distortion and other symptoms relevant for assessment of acoustic performance.
