Bone conduction microphone: Head sensitivity mapping for speech intelligibility and sound quality

The goal of the study was to assess intelligibility and quality of speech recorded through a bone conduction microphone (BCM) located at various points on the talker’s head. Ten words spoken by a female and a male talker in a quiet environment were recorded through a BCM placed at eight different locations on the talker’s head. The sound levels of the recorded signals were normalized and the signals were presented to 33 listeners through a pair of AKG K-240DF sheadphones. In two separate listening sessions, the participants were asked to evaluate the speech intelligibility and sound quality of each word. A total of 640 signals were presented to each listener during each session (2 talkers x 10 words x 8 locations x 4 repetitions). The results of the study indicated that BCM placement on the forehead and temple of the talker resulted both in the highest intelligibility and quality of the recorded speech with rating scores significantly higher than those for all other locations.