Military operators face a number of unique challenges in using personal hearing protection devices in operational environments. An operator could be exposed to ambient noise in excess of 100 dBA in an aircraft or an armoured vehicle, impulse noise in excess of 160 dB SPL from weapon fire, or extreme quiet while patrolling and listening carefully for threats. In all cases, situational awareness and clear radio communications are required. The development of tactical communication and protection systems (TCAPS) has enabled military operators to have integrated radio communication with hearing protection, together with the capability for enhanced ambient listening. While the effects of conventional hearing protection devices on speech understanding and sound localization are known, the features of TCAPS add additional complexities that become apparent when conducting human research experiments. These features include the placement of external microphones, ranges of volume settings for ambient sound, and different styles of circumaural and in-ear headsets. This paper provides a human factors perspective of TCAPS, summarizing studies that we have completed on sound localization, speech understanding with and without hearing loss, and communication with non-native English speakers. Benefits and drawbacks of using TCAPS for different users in different types of operational settings will also be discussed.
