Voice transmission through vibration pickups
Paolo E. Giua · The Journal of the Acoustical Society of America · 1998
Devices that pick up vibrations induced in the body by the speaker voice have been used in speech communication for many years in order to enhance intelligibility in noisy environments. This and other interesting applications seem to justify a study of this ‘‘accelerometric’’ speech in order to obtain useful correlations with the ‘‘microphonic’’ speech. Many factors seem to influence the voice spectrum of the accelerometric speech. A constant general factor is the low-pass filter effect of the acoustical bone conduction. But the main one seems to be the coupling of the voice to the bony transmission channel. This coupling is phoneme dependent. For instance, voiced stop consonants are more amplified than voiced fricatives, while vowels are modified according to their qualities. Moreover speaker features and accelerometer features are to be taken into account. The present results refer to an accelerometer inserted in the ear canal. Main features of this type of accelerometric speech are shown and intelligibility measurements as a function of speakers and their vocal effort are reported. An attempt to recover microphonic speech corrupted by noise by means of a simultaneous accelerometric speech is described.