Localizable auditory warning pulses

Abstract

Three important forms of information available to the listener may be identified in any auditory warning: what (semantic), where (location) and when (perceived urgency). Each form is addressed in the present design study of auditory warning pulses. Recordings were made via a dummy head, and were presented dichotically to listeners in a left/right localization task. The first experiment identified a suitable notched noise component for providing location information in the pulse stimulus. The second experiment required participants to simultaneously identify a distinct tonal signature and the location of the sound when they were presented with one of three tonal types, or one of three compound (tone plus noise) stimuli. Response accuracy and response latency for this identification and localization task were significantly better with the compound than with tone alone stimuli. Perceived urgency of compound complex tone plus noise stimuli was investigated in the third experiment. While there may be a trade-off between localization acuity and perceived urgency, the addition of noise components to the auditory warning pulse was shown to enhance the location information available to the listener. It is suggested that some auditory warning designs will benefit from the simultaneous provision of what and where forms of information in the sounds.

Keywords:

• Auditory displays
• Localizable alarms

Acknowledgements

This research was funded by the Economic and Social Research Council, in conjunction with Sound Alert Ltd. The authors wish to extend their thanks to Dr Nick Hill of the Department of Psychology, University of Essex, UK, for providing signal generation software, experimentation software and related support. Thanks also goes to Professor Tony Chapman, formerly of the School of Psychology, University of Leeds, UK, and Dr Nigel Holt, formerly of Department of Psychology, University of York, UK, for their support at different stages of the project.