Transducer hysteresis contributes to "stimulus artifact" in the measurement of click-evoked otoacoustic emissions

Click-evoked otoacoustic emissions from the human ear are typically several orders of magnitude smaller than the stimuli that elicit them-a measurement technique that attempts to cancel the stimulus signal from the recorded waveform is therefore typically employed. In practice, an imperfect cancellation of the stimulus is achieved, leaving a "stimulus artifact" that obscures the early part of the emission. Input-output nonlinearities of the transducers used in recording emissions are acknowledged as one source of the stimulus artifact. Here an additional source of this artifact, related to hysteresis in the magnetic "receivers" (loudspeakers) used in such recordings, is identified and discussed.