Impact of a Bone Conduction Communication Channel on Multichannel Communication System Effectiveness

Abstract

Objective: In this study, the impact of including a bone conduction transducer in a three-channel spatialized communication system was investigated. Background: Several military and security forces situations require concurrent listening to three or more radio channels. In such radio systems, spatial separation between three concurrent radio channels can be achieved by delivering separate signals to the left and right earphone independently and both earphones simultaneously. This method appears to be effective; however, the use of bone conduction as one channel may provide both operational and performance benefits. Method: Three three-channel communication systems were used to collect speech intelligibility data from 18 listeners (System 1, three loudspeakers; System 2, stereo headphones; System 3, stereo headphones and a bone conduction vibrator). Each channel presented signals perceived to originate from separate locations. Volunteers listened to three sets of competing sentences and identified a number, color, and object spoken in the target sentence. Each listener participated in three trials (one per system). Each trial consisted of 48 competing sentence sets. Results: Systems 2 and 3 were more intelligible than System 1. Systems 2 and 3 were overall equally intelligible; however, the intelligibility of all three channels was significantly more balanced in System 3. Conclusion: Replacing an air conduction transducer with a bone conduction transducer in a multichannel audio device can provide a more effective and balanced simultaneous monitoring auditory environment. Application: These results have important design and implementation implications for spatial auditory communication equipment.