The Effect of DC Biasing on Nonlinear Compensation of Small Loudspeakers

To compensate for the nonlinear distortions of loudspeakers, the signal is passed through a predistortion filter placed between the audio signal source and the loudspeaker. Exact nonlinear precompensation of loudspeakers based on the Volterra or Volterra-Wiener models results in a predistorted signal that may contain a time-varying DC offset. This paper describes the source of this DC offset and presents experimental evidence verifying that offsetting the drive signal of a loudspeaker indeed results in higher sound quality. The explanation for this phenomenon is also given.