title: Atmospheric effects on voice command intelligibility from acoustic hail and warning devices.
abstract: Voice command sound pressure levels (SPLs) were recorded at distances up to 1500 m. Received SPLs were related to the meteorological condition during sound propagation and compared with the outdoor sound propagation standard ISO 9613-2. Intelligibility of received signals was calculated using ANSI S3.5. Intelligibility results for the present voice command indicate that meteorological condition imposes little to no effect on intelligibility when the signal-to-noise ratio (SNR) is low (<-9 dB) or high (>0 dB). In these two cases the signal is firmly unintelligible or intelligible, respectively. However, at moderate SNRs, variations in received SPL can cause a fully intelligible voice command to become unintelligible, depending on the meteorological condition along the sound propagation path. These changes in voice command intelligibility often occur on time scales as short as minutes during upward refracting conditions, typically found above ground during the day or upwind of a sound source. Reliably predicting the intelligibility of a voice command in a moderate SNR environment can be challenging due to the inherent variability imposed by sound propagation through the atmosphere.
authors.affiliation: Graduate Program in Acoustics and Applied Research Laboratory, The Pennsylvania State University, PO Box 30, State College, Pennsylvania 16804, USA. jason.bostron@gmail.com
authors.forename: Jason H
authors.initials: JH
authors.lastname: Bostron
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Brungart
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Barnard
authors.forename: Timothy E
authors.initials: TE
authors.lastname: McDevitt
mesh_terms: D000162:Acoustics; D059028:Airports; D001272:Atmosphere; D003146:Communications Media; D004189:Disaster Planning; D004630:Emergencies; D006801:Humans; D008891:Military Science; D008962:Models, Theoretical; D013061:Speech Acoustics; D013065:Speech Intelligibility; D014831:Voice; D014887:Weather