Human perception of apparent direction and movement of aircraft noise

Abstract

NASA Langley Research Center is developing an Aircraft Noise Reduction Laboratory which will, among other things, have the capability of simulating both indoor and outdoor home-like settings which provide visual and auditory realism. Although visual realism is easily understood, there was some question as to just what constitutes auditory realism. While it is clear that loudness changes, spectrum changes, and Doppler shifts are easily perceived by people in their homes, it is not so clear just what is perceived in regard to apparent motion and direction of real aircraft flying overhead or off to the side. In order to resolve this question, a study was conducted in which subjects, both indoors and outdoors, made judgments of apparent direction and movement of various large and small aircraft which were flown a number of times over the house in which the subjects were located. Results of this study will be discussed.