Single-channel vibrotactile feedback for voicing enhancement in trained and untrained perceivers

Abstract

Auditory speech intelligibility can be enhanced by integrating information from other modalities, e.g., vision [Sumby & Pollack 1954, J. Acoust. Soc. Am. 26: 212] or direct manual touch [Gick et al. 2008. J. Acoust. Soc. Am. 123: EL72]. There are, nonetheless, many circumstances where shared visual attention may be hard to establish, or where in-person contact may be infeasible (e.g., in a noisy collaborative environment). To test the feasibility of using vibrotactile feedback to enhance intelligibility under noisy conditions, we use a portable voice-coil-based transducer that provides vibrotactile stimulation similar to laryngeal vibrations. Participants were asked to discriminate between minimal pairs in noise. These were distinguished in voicing and vowel height. Participants were asked to wear a vibrator on their fingers, or on their suprasternal notch. We contrasted vibrator placement with different vibration styles, such as a constant vibration on voicing, or vibrations driven by the amplitude envelope of the speech signal. In untrained perceivers we found that vibrotactile feedback increased accuracy regardless of placement. This effect, though significant, was not strong enough to be useful for everyday speech enhancement. These results, and those of a follow-up study with trained perceivers, will be reported. [Funding from NSERC.]