I know of authors who listen to certain soundtracks while they're writing to inspire them to write with emotion or to add authenticity to their story. But what I'm thinking of today are the sounds you hear while reading a book.
It's important to incorporate sensory details (sight, sound, touch, smell, taste) into a story to transport the reader. One of the details that I appreciate when I'm reading is narrative that conveys the sounds the characters are hearing.
If the setting is outside, I'd like the author to find a unique way to describe the sounds the character might hear. I'd like the description to deepen the characterization of the protagonist—tell me if the sounds are soothing or terrifying, depending on the character's circumstances.
If your character is in a city, I'd expect to hear sounds of traffic or snatches of conversation at some point in the novel. What would the character be thinking in reaction to this city noise? Please, tell me.
Or perhaps your character is at the beach and there is background noise to an important conversation. How would that sound enhance your story? How could you work it into the theme of the book?
It's windy today in south Denver. The sound of the wind can add tension and drama to a story. You could write about the sound of dried leaves scudding across a parking lot, or a tree limb groaning as it rubs a fence, or the writer can add whimsy and have the wind tickle a set of outdoor chimes.
Just thinking and hoping I've inspired you to think as well.