Perception of Nonlinear Distortion in Music Signals Reproduced by Microspeakers

A lot of work has focused on compensating nonlinear distortions of the microspeaker under large excitation, yet it is unclear at which level the effect of nonlinear distortion is imperceptible or not annoying. In this study virtual listening tests were performed to evaluate the deterioration of sound quality in music signals with different levels of nonlinear distortion by a microspeaker. Binaural recordings of the music played by the microspeaker were made at different voltage levels, adjusted to the same RMS power, and afterwards reproduced by a low distortion reference headphone. The “double-blind triple-stimulus with hidden reference” method was used in the listening tests. Listeners were required to not only discern the distortion, but also rank the severity of the distortion. The effects of several factors including subject, program material and distortion level on the perceived distortion are discussed.