X-Plane uses FMOD as its new sound engine; you can use FMOD’s authoring tools to create highly realistic sounds for your aircraft. FMOD is a high quality commercial sound engine and sound authoring environment for games. 
Guides
| Title | Updated | Description | 
|---|
| B738 FMOD Studio Sources | 23 Jan 2024 | Complete B737-800 FMOD Studio project as shipped in X-Plane 12 | 
| FMOD 2.0 Upgrade Notes | 29 Sep 2022 | How to use FMOD 2.0 with X-Plane 12. | 
| Using FMOD with X-Plane | 9 May 2022 | This guide explains how to use the commercial FMOD sound engine to add custom sounds to aircraft in  X-Plane 11. | 
Tips & Tricks
Reference
| Title | Updated | Description | 
|---|
| FMOD Event Parameters for X-Plane | 30 Dec 2021 | Explanation on using cone & dataref parameters with FMOD sound. | 
File Formats
| Title | Updated | Description | 
|---|
| Sound (.snd) File Format Specification | 19 Aug 2024 | X-Plane .snd files integrate custom FMOD sound into an aircraft. |