The PING! project's purpose is to develop an interactive audio based navigation system for the visually impaired. The results will be used for an installation in the New York Hall of Science. Begun in 2003, As part of a National Science Foundation award to the Touch Graphics Company, Western Michigan University was sub-contracted to perform research in the areas of likeability, localization, and navigability of attractor sounds to be included in PING!. With the culmination of research resulting in suggested sounds to be used and research and development of a loudspeaker mount to be installed in the New York Hall of Science installation. more >>
The purpose of this project is to refine and test an acoustic virtual display
(AVD) system that will ultimately be used to investigate the auditory space perception
abilities of blind and visually impaired individuals. This project will be completed
with support from the faculty of the WMU Blind Rehabilitation department and
faculty of the Bill Wilkerson Speech and Hearing Center of Vanderbilt University,
located in Nashville, Tennessee. Our goal is to develop a two-speaker version
of an existing multiple-speaker AVD system, so that we can construct a portable
two-speaker AVD system at WMU. Access to such a system at WMU dramatically enhances
our research capacity in auditory space perception of persons with blindness
and low vision. Our initial research efforts involve an investigation of adults'
abilities to detect small changes in the trajectories of moving sound sources,
and to isolate and track movement of a specific sound source in the presence
of masking sounds. Both of these abilities are important components of independent
movement without vision.
Our research in this area has been focused on the development of a control technique for reduction of sound radiated from vibrating structures based on minimization of local volume displacement, velocity, or acceleration of a vibrating structure. Multiple, single-input/single-output cancellation devices are used. Each device controller employs a motion sensor and an acoustic actuator (loudspeaker). The motion sensor signal is related to the local volume displacement of the structure which is then reduced by a loudspeaker driven with an equal but opposing volume displacement. Our work has resulted in the successful implementation of this technique for uniformly vibrating radiators (using an accelerometer as a motion sensor) as well as the development of this technique for reduction of sound radiated from a vibrating beam. A PVDF sensor was used for measurement of local volume displacement of the beam. This sensor was used in conjunction with an internal pressure sensor mounted in the loudspeaker enclosure. Sound reductions of up to 20 dB were achieved within a narrow range of vibration frequencies (centered around the first beam mode).