Don’t let the title fool you: “The History of Sound” is an awfully muted affair. Muted in color, performance, tenor and tone, Olivier Hermanus’ doleful ethnomusicologist romance premiered in Cannes to a commensurately muffled response.

Narrated by Chris Cooper – who later shows up as the aged protagonist in the film’s coda, delivering its most affecting performance right before the credits roll – “The History of Sound” otherwise follows the Kentucky-born Lionel when he resembles Paul Mescal. Lionel’s a farm-boy introvert blessed with a peculiar form of synesthesia – for him, the whole world’s a symphony, making for a man of few words and deep sensitivity.

While studying at the Boston Conservatory, Lionel’s senses spark to life when he hears the suave Yankee David (Josh O’Connor) singing a familiar folk ballad. The two begin swapping songs as a form of flirtation, becoming an item the moment David, seated...