title: Effects of Bone Vibrator Position on Auditory Spatial Perception Tasks.
abstract: OBJECTIVE
  This study assessed listeners' ability to localize spatially differentiated virtual audio signals delivered by bone conduction (BC) vibrators and circumaural air conduction (AC) headphones.
  
  
  BACKGROUND
  Although the skull offers little intracranial sound wave attenuation, previous studies have demonstrated listeners' ability to localize auditory signals delivered by a pair of BC vibrators coupled to the mandibular condyle bones. The current study extended this research to other BC vibrator locations on the skull.
  
  
  METHODS
  Each participant listened to virtual audio signals originating from 16 different horizontal locations using circumaural headphones or BC vibrators placed in front of, above, or behind the listener's ears. The listener's task was to indicate the signal's perceived direction of origin.
  
  
  RESULTS
  Localization accuracy with the BC front and BC top positions was comparable to that with the headphones, but responses for the BC back position were less accurate than both the headphones and BC front position.
  
  
  CONCLUSIONS
  This study supports the conclusion of previous studies that listeners can localize virtual 3D signals equally well using AC and BC transducers. Based on these results, it is apparent that BC devices could be substituted for AC headphones with little to no localization performance degradation.
  
  
  CONCLUSIONS
  BC headphones can be used when spatial auditory information needs to be delivered without occluding the ears. Although vibrator placement in front of the ears appears optimal from the localization standpoint, the top or back position may be acceptable from an operational standpoint or if the BC system is integrated into headgear.
authors.affiliation: North Carolina Agricultural and Technical State University, Greensboro, North Carolina mcbride@ncat.edu.
authors.forename: Maranda
authors.initials: M
authors.lastname: McBride
authors.affiliation: North Carolina Agricultural and Technical State University, Greensboro, North CarolinaU.S. Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MarylandNational Center for Rehabilitative Auditory Research, Portland, Oregon.
authors.forename: Phuong
authors.initials: P
authors.lastname: Tran
authors.affiliation: North Carolina Agricultural and Technical State University, Greensboro, North CarolinaU.S. Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MarylandNational Center for Rehabilitative Auditory Research, Portland, Oregon.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Pollard
authors.affiliation: U.S. Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Letowski
authors.affiliation: National Center for Rehabilitative Auditory Research, Portland, Oregon.
authors.forename: Garnett P
authors.initials: GP
authors.lastname: McMillan
mesh_terms: D000293:Adolescent; D000328:Adult; D001844:Bone Conduction / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012886:Skull / Q000502:physiology; D013017:Sound Localization / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D013647:Task Performance and Analysis; D014732:Vibration; D055815:Young Adult
keywords: 3D; auditory perception; azimuth; bone conduction; localization