Objectives:
This study investigated the impact of visual input—specifically, speaker-to-listener distance (SLD) and room size—on voice production. Building on existing evidence that visual cues can influence vocal intensity, we used immersive virtual reality (IVR) to create controlled visual environments to examine how room size and SLD affect vocal output intensity, both independently and in combination
Methods: Fifteen vocally healthy participants completed three speaking tasks—sustained /ah/, the CAPE-V phrase “We were away a year ago,” and spontaneous connected speech. Participants were exposed to eight randomized IVR conditions (small room, large room, 3m SLD, 15m SLD, small room with 1m and 3m SLD, large room with 3m and 15m SLD) following initial training and calibration. Voice recordings were collected for later acoustic analysis. Auditory input was held stable across conditions so results would reflect varying visual conditions alone.
Results: Significant differences emerged, showing that increased SLD resulted in higher sound pressure levels (SPL). However, variations in room size did not produce significant changes in SPL.
Conclusion: This study adds to critical data regarding the role of visual input in voice regulation, suggesting that SLD may be the primary driver of visual impact on vocal intensity rather than room size. These findings provide insights for voice training and therapy, emphasizing the importance of realistic visual contexts and moreover, communicative intent.