The game was requested to have vertically adaptive music with layers coming in and out to match the pacing of the level. This was somewhat difficult since combat was so fast, it was jarring to have layers rapidly moving around in a dynamic system based on if the player was in combat or not. As a solution to this, I created a music trigger system that audio and our level designers could use to have it so certain rooms or areas could be marked up to play certain stems. That way we had more bespoke control over when layers could fade in and out throughout the level. This is an example of how it functioned.
This specific trigger was relatively simple. All it did was check if the player had crossed it, and came with several options to configure the trigger's behavior. The user could decide if the trigger should be reusable, should be temporary, destroyed on use, as well as many other basic functions to control the music.