Since the emergence of cognitive linguistics in the 1980s, metaphor has been regarded as one of the fundamental areas of language and cognition. Nevertheless, few empirical studies have focused on synesthetic metaphors, which involve transfer from one sensory domain to another. This study provides a theoretical and empirical analysis of synesthetic metaphors for sound such as bright sound and sharp voice. Corpus analysis of literary works shows that synesthetic metaphors are similar in English and Japanese. However, some differences exist in the types of linguistic expressions that accompany the metaphors (e.g., onomatopoeia) and the aspects of sounds that are described (e.g., sound source). Based on the experimental data involving three different types of sounds - environmental sounds, music, and speech - it becomes evident that synesthetic metaphors are related to the physical aspects of stimuli as well as cultural tendencies. The study brings together research findings on metaphor and sound from wide-ranging fields, and should be useful to metaphor researchers in linguistics, philosophy, literature, music theory, anthropology, psychology, and neuroscience.