Abstract: By means of an active filter with free-field sound exposure from the front, a system is provided which assures a frequency response of a microphone's transmission functions which is comparable with that of a measurement microphone, so that this system on the one hand analyzes acoustic phenomena in the conventional manner and, additionally, in the case of reproduction via a free-field, distortion-corrected headset to the eardrums of a listening person, generates the same sound pressure signals as if the person were located at the place of sound recording, while, on the other hand, in the case of reproduction via loudspeakers no annoying acoustic contamination occurs. The entire artifical head system is designed for either a.c. or battery operation and is combined with an analog or digital recording unit to produce a self-sufficient recording and reproduction system.

Abstract: An electroacoustic simulation method and apparatus for imitating electroastically the human outer ear having transmission properties corresponding to those of the human outer ear when exposed to sound in the free field is proposed, wherein the physical acoustical causes of the outer ear, the head, the upper part of the body, the pinna rim, and the like, are represented mathematically by simple partial models and approximated in the form of electric circuits containing circuit elements such as high-pass filters, low-pass filters, all-pass filters . . . and the like, with the possibility to vary certain properties of the circuit elements continuously by varying the parameters so that arbitrary directions of sound incidence can be adjusted infinitely in the horizontal and median planes.

Abstract: An artificial head acoustic measuring system includes a construction including portions configured to appear as human shoulders, head and ears on both sides of the head with auditory canals and microphones disposed in the auditory canals. The head portion comprises partial bodies corresponding to mean data of test persons with respect to dimensions and relative positions. The partial bodies comprise regular geometric bodies calibrated with respect to sound reflexion, diffraction and resonance behavior to define a reproducible artificial-head transmission function related to the outer geometric configuration of the construction.