Simpler realization of ear simulators using tuning stubs instead of Helmholtz resonators

Abstract

The Zwislocki- and the IEC711- ear simulators are the widely accepted standard devices whenever a mechanically stable representation of the human ear impedance is needed, e.g., for earphone calibration. Though the design of these simulators is rather complex [see Burkhard, J. Audio Eng. Soc. 25, 1008–1015 (1977) for some related problems], they were not intended to reveal “correct” results above 10 kHz. Recently measurement techniques for obtaining ear impedances data up to 20 kHz have become available [Joswig, Acoust. Soc. Am. Suppl. 1 69, S14 (1981) and Hudde, Acoust. Soc. Am. 73, 24–31, 242–247 (1983)]. To construct an ear simulator for high frequencies we studied the effect of closed-end stubs of small diameter to replace the lumped-parameter resonators used so far. These stubs do not require any special damping material. The geometrical tolerances are high. An a priori error estimation is possible during computer simulation. Predicted and measured results agree well enough to make a posteriori fine tuning redundant.