Voice Calling Detection Distance in Land Search and Rescue

The distance at which shouts from a caller remain intelligible to a listener were measured in a wilderness coniferous forest and separately in an aspen parkland forest with the aid of members of the Edmonton Regional Search and Rescue Association. Values were determined for calling at an average sound intensity of approximately 88 dB at 1 m by both a male and a female caller. An equation based on existing models in the sound engineering literature was then developed that predicts this distance. KEY WORDS: voice detection range, acoustic search, calling, listening, shouting, speech intelligibility