Change audio middleware

Description

OpenHellion uses the Wwise audio middleware to render sounds using complicated parameters (RTPC) and sound effects with an advanced Audio Editor.

Wwise has three main downsides:

1. It has a license process where you have to apply each time you want a license using a form that isn't very easy.
2. This also forces you to be logged in to an AK account when using the editor.
3. The editor does not support linux devices.

Alternatives

Two main alternatives exist: Unity Audio and FMOD.

Unity Audio is by far the simplest solution. It is installed into all Unity projects by default and supports most of the features that a game like this need. It is also fairly flexible, and can be extended greatly with scripts and native plugins. The main downside is that it does not have RTPC and insufficient effects, so these require custom code and plugins like Resonance Audio.

FMOD is similar to both Wwise and DAW's like Ableton Live, which might make it more accessable while retaining the same set of features. Migration wouldn't be difficult either, since they're largely based on the same concepts.

The main downside with FMOD is that it is proprietary and has its own licencing terms that make adoption more difficult. In addition, it is a separate program that needs to be downloaded, and more scripts to be integrated into Unity.

The issue does not name files, tests, or a chosen replacement. Start by locating the existing Wwise integration and comparing Unity Audio and FMOD against the listed requirements. Before implementation, agree on the target middleware and migration scope; done criteria should cover replacing the current integration while retaining the required audio features.