uae_sound_stereo_separation
The option documentation is properly formatted yet
Category: Audio Default: 10 Example: 7 Range: 0 - 10 Type: integer
This option controls the amount of cross-mixing of the stereo channels. Set to 10 (100%) to have full separation (no mixing), and 0 (0%) to have the stereo channels completely mixed together.
Source: https://github.com/FrodeSolheim/fs-uae/blob/master/docs/options/uae_sound_stereo_separation