Earphone-coupling technique for measuring the temporal characteristics of aural acoustic-immittance devices

This research note describes an earphone-coupling technique that can be used to measure the temporal characteristics of acoustic-immittance instruments. The primary advantage of the earphone-coupling procedure in comparison with the procedure described by Popelka and Dubno (1978) is that the temporal measures are not contaminated by delays and irregularities in the coupler sound-pressure level associated with the pressure system. The latencies of two instruments (Grason-Stadler, Model 1723) were compared using this earphone-coupling procedure and the Popelka-Dubno procedure. The latency measures were in good agreement following a correction for the delay associated with the pressure tubing in the latter procedure. The technique described is offered as an alternative to the Popelka-Dubno procedure in the absence of a modified 2-cm3 coupler, particularly for instruments with complex pressure systems.