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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.

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data so.1rces gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collectiof of information, including suggestions for reducing the burden, to the Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents should b4 aware that notwithstanding any other provision of Law, no person shall be subject to any penalty for falling to comply with a collection of information if it does not display a currently velic OMB control number. orifices, including the ears, to achieve minimal protection. Additionally, warfighting involves operating in very close proximity to loud equipment, from which the noise can degrade an individual's auditory perception, and over time can degrade general performance. Common hearing protection and occlusion isolates the warfighter from the environment, deflating situational awareness, confidence, and effectiveness, thus putting the warfighter at high risk and compromising his ability to detect and assesm threats. Often, soldiers are so uncomfortable with the isolation of hearing protection that they will choose to go without hearing protection and expose themselves to painful and harmful noise, which can result in deafness and reduced effectiveness as warfighters. This effort includes a survey of relevant head-borne hear-through auditory systems, a selection of approaches to a transparent hearing solution, implementation of the approaches, and evaluation. PLEASE DO NOT