The accuracy of absolute localization judgments for speech stimuli

Area of Science:

• Acoustics
• Psychoacoustics
• Human-Computer Interaction

Background:

• Three-dimensional auditory displays utilize acoustic stimulation for spatial information.
• Localization of communication signals, particularly speech, in these displays is understudied.
• Understanding speech localization is crucial for effective spatial audio technology.

Purpose of the Study:

• To investigate the human ability to localize speech targets in a 3D auditory space.
• To compare speech localization accuracy with the localization of non-speech (click) targets.
• To identify specific dimensions of spatial localization that are more difficult for speech.

Main Methods:

• Participants localized single-word speech targets (male/female) and click targets.
• Targets were presented from 239 distinct locations in azimuth and elevation (-45° to +90°).
• Localization accuracy was measured across left/right, front/back, and up/down dimensions.

Main Results:

• Left/right localization accuracy was comparable for speech and click targets.
• Speech targets resulted in significantly more front/back reversals than click targets.
• Elevation judgments were less accurate for speech compared to click targets.

Conclusions:

• Speech localization in 3D auditory displays is less accurate than non-speech sound localization.
• Front/back and up/down localization present particular challenges for speech stimuli.
• Designers of 3D auditory displays must consider these limitations to ensure accurate spatial information delivery.