Speech-based distance cueing in virtual auditory displays

One of the greatest weaknesses of current virtual audio displays is their inability to produce robust distance cues. There is, however, reason to believe that the systematic changes that occur in human speech as the loudness of the voice increases can provide distance information in a virtual audio display. In this experiment, speech samples ranging from quiet whispers to loud shouts were processed to simulate live human talkers at 9 distances from 0.25 m to 64 m, and were presented over headphones to listeners in an outdoor environment. The resulting distance judgments indicate that vocal effort has a strong influence on the perceived distance of speech, and that the effects of vocal effort are consistent across a range of talkers, utterances, and listeners. Thus, it appears that speech-based distance cues are capable of providing salient distance information in virtual audio displays.