Tuyen V. Tran
Tomasz R. Letowski
Kim S. Abouchacra
US Army Res. Lab., AMSRL-HR-SD, Bldg. 520, Aberdeen Proving Ground, MD 21005-5425
A series of experiments was conducted to evaluate 3D auditory beacons to be used by drivers of remote-controlled vehicles. The auditory beacons were generated from an external sound source, conditioned using the Convolvotron(trademark) and then presented through Sennheiser HD-580 earphones. In addition, a pink noise masker was presented through an overhead loudspeaker at a level of 80 dBA measured under the earphones. Ten listeners with normal hearing were asked to (1) judge sound quality of nine auditory beacons, and (2) move a beacon from a predetermined starting location to a position directly in front of the listener in the 3D display. The beacons differed regarding type of sound as well as rate and mode (continuous versus noncontinuous and single versus oscillating sound source) presentation. Results of the experiments indicate that listeners preferred (1) continuous versus interrupted presentation of the beacons, (2) nonspeech versus speech beacons, and (3) a rate of 1.1 repetitions per second over 0.7 or 2.5 repetitions per second. Mode of presentation did not affect the overall localization accuracy or the number of front versus back confusions made by the listeners. Results of the experiments will assist in the selection of beacons for auditory displays used for operation of remote-controlled vehicles.