When people talk about horror in things such as movies and video games, outside of visuals, what is the most important thing? The audio, I don't know how many horror games easily get ruined by one bad sound effect or a false jump scare audio in a movie messing with the audience and potentially annoying them. Yet good sound, the right audio can heighten the fear brought on in ways that the subconscious mind can only truly understand or turn a beloved song into a hint of a villain's approach such as how Fallen turned a Rolling Stones' song into the cue that things were about to get supernatural. Getting that experience of sound can be done in the written word too, though it is a bit trickier.
The easiest way to put sound into a horror is of course, dialogue. Voices allow for audio to appear in the reader's mind, especially if a lot of attention is drawn to how they sound. Was the voice deep or was it high pitched? Did he speak with fear or uncertainty? Sometimes even the flow of the dialogue can lead to understandings of how it is supposed to sound. For example, look at this dialogue and see what you can make of how it is supposed to be “said”:
“Could you two stop it, I am trying to win here,” Ian added, ending the argument quickly. After taking his turn at the chessboard, Jake smiled as he moved his queen.
“And that's checkmate.”
“How in the-oh, fuck you.”
“We both know you don't like boys.”
“Shut up asshole.”
Ian, Jake, Ian, Jake, Ian is the dialogue order isn't it? You didn't need to tell the audience who was speaking each line when the first paragraph establishes the order by actions. Jake moving the chess piece leads to him stating the checkmate and everything flows from there. Also, you could hear the annoyance from Ian couldn't you? The language gives the context of his current mood, while Jake's is relaxed, taunting even. You can hear their conversation in your mind with these contextual clues. Sound infusing itself into writing without an audio book.
Another good trick is every comic book's favorite word: onomatopoeia. Pow, bam, ka-chunk, thwap, buzz, thump, and a thousand other words can easily be used to help inject some sound into your story. The chitter of mice rushing by your feet, the whoosh of a quick breeze that goes by as fast as it came, the rustle of a tree in the distance, you can hear these things in your mind as much as I am currently hearing the sloshing of a dish washer running in my apartment. You can hear it too, now that I have typed it out and as it makes a slamming clack sound as it finishes one step and moves onto another.
Nothing brings your audience in more than including more of their senses into their experience, and sound is an easy way to do so. So, tell me while your keyboard clicks away under your fingertips, what are your favorite ways to bring sound into the equation of story? I'd love to hear them.