Engineering topics

Chapin, William L.

Publications and source records attributed to Chapin, William L..

3 records

NASA NTRS2015

The NASA Auralization Framework and Plugin Architecture

NASA has a long history of investigating human response to aircraft flyover noise and in recent years has developed a capability to fully auralize the noise of aircraft during their design. This capability is particularly useful for unconventional designs with noise signatures significantly different from the current fleet. To that end, a flexible software architecture has been developed to facilitate rapid integration of new simulation techniques for noise source synthesis and propagation, and to foster collaboration amongst researchers through a common releasable code base. The NASA Auralization Framework (NAF) is a skeletal framework written in C++ with basic functionalities and a plugin architecture that allows users to mix and match NAF capabilities with their own methods through the development and use of dynamically linked libraries. This paper presents the NAF software architecture and discusses several advanced auralization techniques that have been implemented as plugins to the framework.

Aumann, Aric R.↗

NASA NTRS2010

Acoustic Calibration of the Exterior Effects Room at the NASA Langley Research Center

The Exterior Effects Room (EER) at the NASA Langley Research Center is a 39-seat auditorium built for psychoacoustic studies of aircraft community noise. The original reproduction system employed monaural playback and hence lacked sound localization capability. In an effort to more closely recreate field test conditions, a significant upgrade was undertaken to allow simulation of a three-dimensional audio and visual environment. The 3D audio system consists of 27 mid and high frequency satellite speakers and 4 subwoofers, driven by a real-time audio server running an implementation of Vector Base Amplitude Panning. The audio server is part of a larger simulation system, which controls the audio and visual presentation of recorded and synthesized aircraft flyovers. The focus of this work is on the calibration of the 3D audio system, including gains used in the amplitude panning algorithm, speaker equalization, and absolute gain control. Because the speakers are installed in an irregularly shaped room, the speaker equalization includes time delay and gain compensation due to different mounting distances from the focal point, filtering for color compensation due to different installations (half space, corner, baffled/unbaffled), and cross-over filtering.

Faller, Kenneth J., II↗

NASA NTRS1992

Virtual environment display for a 3D audio room simulation

The development of a virtual environment simulation system integrating a 3D acoustic audio model with an immersive 3D visual scene is discussed. The system complements the acoustic model and is specified to: allow the listener to freely move about the space, a room of manipulable size, shape, and audio character, while interactively relocating the sound sources; reinforce the listener's feeling of telepresence in the acoustical environment with visual and proprioceptive sensations; enhance the audio with the graphic and interactive components, rather than overwhelm or reduce it; and serve as a research testbed and technology transfer demonstration. The hardware/software design of two demonstration systems, one installed and one portable, are discussed through the development of four iterative configurations.

Chapin, William L.↗