Sound plays an important role in opening title sequences by setting the mood for the film. For horror films, the music should start quietly and get louder to build tension and anticipation in the audience. The sound should also match what is happening on screen, whether it is diegetic, non-diegetic, asynchronous, or synchronous. By learning about different types of sound and how it relates to the genre and action, title sequences can effectively introduce the audience to the film's tone and story.