Acoustic performance of an installed real-time three-dimensional audio system.

Abstract

The Exterior Effects Room (EER), located at the NASA Langley Research Center, is a facility built for psychoacoustic studies of aircraft community noise. Recently, the EER was significantly upgraded to allow for simulation of aircraft flyovers in a 3-D audio and visual environment. The upgrade included installation of 27 satellite and 4 subwoofer loudspeakers that are driven by a real-time audio server. The audio server employs an implementation of the vector base amplitude panning method to position virtual sources at arbitrary azimuth and elevation angles in the EER. Real-time application of filters, time delays, and gains are required to compensate for installation effects, including those associated with the irregular room geometry, colorization due to varying loudspeaker installations, and crossover filtering. The authors previously showed [J. Acoust. Soc. Am., 127, 1969 (2010)] that color compensation and crossover filtering could be achieved for satellite and subwoofer loudspeakers. However, the resulting FIR filters were too long (32 768 taps) to implement in real-time. The focus of this work is on the development of reduced-length surrogate IIR filters and on the measurement of the acoustic performance of the installed real-time system.

Annoyance to Noise Produced by a Distributed Electric Propulsion High-Lift System

“…The psychoacoustic tests were performed in the NASA Langley Research Center (LaRC) Exterior Effects Room (EER) 15 during the period September 15-18, 2015, in accordance with an approved NASA LaRC Institutional Review Board review of a human subject test application entitled "Distributed Electric Propulsion Phase 1" (DEP-1-2015).…”

Initial Investigation into the Psychoacoustic Properties of Small Unmanned Aerial System Noise

“…The test was conducted in the Exterior Effects Room (EER 19 ) at the NASA Langley Research Center in Hampton, Virginia. The EER is a small, acoustically-treated auditorium with a 31-channel sound reproduction system capable of simulating 3D spatialization of point-source sounds in real time.…”