We investigate the dynamics of sensory integration for perceiving musical performance, a complex natural behavior. Thirty musically trained participants saw, heard, or both saw and heard, performances by two clarinetists. All participants used a sliding potentiometer to make continuous judgments of tension (a measure correlated with emotional response) and continuous judgments of phrasing (a measure correlated with perceived musical structure) as performances were presented. The data analysis sought to reveal relations between the sensory modalities (vision and audition) and to quantify the effect of seeing the performances on participants' overall subjective experience of the music. In addition to traditional statistics, functional data analysis techniques were employed to analyze time-varying aspects of the data. The auditory and visual channels were found to convey similar experiences of phrasing but different experiences of tension through much of the performances. We found that visual information served both to augment and to reduce the experience of tension at different points in the musical piece (as revealed by functional linear modeling and functional significance testing). In addition, the musicians' movements served to extend the sense of phrasing, to cue the beginning of new phrases, to indicate musical interpretation, and to anticipate changes in emotional content. Evidence for an interaction effect suggests that there may exist an emergent quality when musical performances are both seen and heard. The investigation augments knowledge of human communicative processes spanning language and music, and involving multiple modalities of emotion and information transfer.