Speech Intelligibility with Acoustic and Contact Microphones

Abstract : Speech intelligibility of signals obtained with an acoustic microphone and three types of vibration-driven contact microphones was assessed using the Diagnostic Rhyme Test (DRT). Stimulus words were recorded digitally in a reverberant chamber with no noise and with ambient broadband noise intensity at 106 dB(A). Listeners completed the DRT task in the same settings, thus simulating typical environments of a rotary-wing aircraft. Results show that speech intelligibility is significantly worse for the contact microphones than for the acoustic microphone, particularly in noisy environments, and some consonant types are affected more than others. Therefore, contact microphones are not recommended for use in any situation where fast and accurate speech intelligibility is essential.