Sean Kelly’s review published on Letterboxd:
Right down to the fact that the film is presented with open captioning, Sound of Metal is ultimately a film about being deaf and learning to accept it as part of your life. This accomplished by the sound mix of the films, which allows the audience to experience what Ruben’s hearing loss is like, particularly a muffled and/or tinny sound that gives the title of Sound of Metal a bit of a double meaning. In addition, dialogue becomes less important to the film, as the plot moves along and Ruben begins to learn how to communicate through sign language.
Riz Ahmed (Nightcrawler, Rogue One) gives a career-defining performance as Ruben, whose immense denial of the fact that his hearing loss is permanent, results in him taking on similar behaviours to his past as a drug addict, particularly when it involves finding money for an expensive insertion of a hearing aid implant. Even though she has second billing, Olivia Cooke (Ready Player One, Thoroughbreds) as Ruben’s girlfriend Lou becomes less prominent as the plot moves on, though the character does have a memorable scene later in the film with her father Richard (Mathieu Amalric).
Overall, I will say that Sound of Metal is a film about the acceptance of hearing loss that I quite recommend.