  Audio analysis for forensic speaker verification offers unique challenges in
system performance due in part to data collected in naturalistic field acoustic
environments where location/scenario uncertainty is common in the forensic data
collection process. Forensic speech data as potential evidence can be obtained
in random naturalistic environments resulting in variable data quality. Speech
samples may include variability due to vocal efforts such as yelling over 911
emergency calls, whereas others might be whisper or situational stressed voice
in a field location or interview room. Such speech variability consists of
intrinsic and extrinsic characteristics and makes forensic speaker verification
a complicated and daunting task. Extrinsic properties include recording
equipment such as microphone type and placement, ambient noise, room
configuration including reverberation, and other environmental scenario-based
issues. Some factors, such as noise and non-target speech, will impact the
verification system performance by their mere presence. To investigate the
impact of field acoustic environments, we performed a speaker verification
study based on the CRSS-Forensic corpus with audio collected from 8 field
locations including police interviews. This investigation includes an analysis
of the impact of seven unseen acoustic environments on speaker verification
system performance using an x-Vector system.
