Visualized voices: A case study of audio-visual synesthesia

We report a single case study of a synesthete (PS) who has complex visual experiences from sounds, including human voices. Different vowel sounds from different speakers and modified to be of different pitch (f0) were presented to PS and controls who were asked to draw an (abstract) visual image of the sound noting colors, sizes, and locations. PS tended to be more consistent over time than controls. For both PS and controls, the pitch of the vowel influenced the choice of luminance (higher pitch being lighter) and vertical position (higher pitch being higher in space). However, the gender of the speaker influenced the size of the 'image' independently of pitch (vowels from males being larger).