Audio file used by FMOD, a program used for designing game sounds for Xbox, PlayStation, PC, and other platforms; contains a collection of sounds, such as footsteps, ambient noises, or weapon fire; used by the game runtime to load and play the sounds.
FSB files are created when an FMOD project (.FDP file) is built in FMOD Designer. They are created with an .FEV file, which contains the audio event metadata used by the game program code to trigger sounds when the game is being played.
Since FSB and FEV files are the final deliverable for FMOD audio events, they are often seen packaged with game installation files.
NOTE: FMOD Designer is no longer developed. Firelight Technologies replaced it with FMOD Studio, which uses .BANK files instead of FSB files.