I noticed the sound is corrupted on my system when I start A3D sound mode in Elite Force GOG version. I use A3D Alchemy which is working fine in other games, but when I turn on A3D in the sound menu of the GOG version of EF, I hear quite intense positional sound, but it's full of bugs, missing sounds, distorted and screeching noises instead of the samples and sounds that should get played and so on.

I assume it's about the problem already explored in 2012 here in this Vogons forum thread:

https://www.vogons.org/viewtopic.php?t=32985

It seems I would have to use a version of the game which doesn't have the expansion installed to get A3D working (1.2 patch is said to be fine without the expansion in that thread, but I have read others claim it's also a problem). GOG version includes the expansion and is patched to 1.2 by default, so this could very well be the source of the problem

I didn't find much about this issue besides that thread. Did anyone ever accomplish A3D sound for the GOG version? Is there a way I have not yet found to make it work with GOG's version? Having the expansion work with A3D would of course be the best of all options.

Or is there any way to downgrade the GOG version and uninstall the expansion somehow?