Transducer Nonlinearities in Active Sound Applications (vor Ort)
* Presenting author
Abstract:
Modern DSP algorithms used for active cancellation of echoes (AEC) and noise (ANC), beam steering, 3D sound reproduction or multi-zone contrast control model the used loudspeakers as linear systems. However, the nonlinearities inherent in the electro-acoustical transducer generate significant nonlinear distortion in the error signal of the adaptive cancelation system, which becomes audible as a distorted echo, residual noise, and undesired program material in a silent zone or reduces the recognition rate of wake-up commands in smart speakers. This problem can be avoided by using more linear transducers with a larger size, lower efficiency, or higher cost.This paper investigates an alternative solution by using nonlinear control (e.g. Klippel Controlled Sound) in the DSP to actively cancel the nonlinear distortion, to protect the electro-acoustical transducer against overload, and to generate a desired linear overall response which is constant over product life. Details of implementing adaptive nonlinear control in available smart amplifiers (e.g. Nuvoton G60) at low cost and minimum latency are addressed and practical measurements of the improvements and benefits for other active sound applications are presented.
