This is not a question nor is this an instruction. This is just a piece of general information without too much technical details. Someday I might write more technically detailed guide on how to setup a system like what's described here but don't hold your breath waiting that to happen. Feel free to ask and comment if you know more than me, or you want to know more.
Ever since I returned to PR in early 2021, I've been trying to setup my gaming audio as good as it's possible in Windows 10. These are some of the things I've done to make PR sound great.
That being said, I never liked the sound quality, or lack thereof, of SoundBlaster X-Fi cards nor did I like their clumsy drivers and management software. I actually sold my Auzen X-Fi card when it was still almost new in favor of my current sound card, an ancient Asus Xonar Essence STX. So I have very little experience with EAX 5. Maybe in the distant future when it's properly reverse-engineered and implemented in the software I use, I can finally enjoy EAX 5 in its full glory. Until that happens, this is what I got.
One of biggest impact on audio in legacy games was Microsoft's decision to retire DirectSound and DirectSound3D (DS3D). After that there was no more hardware accelerated audio API available, and games had to fall back to inferior software audio.
Thankfully, DirectSound is now quite well reverse-engineered and there is a nice piece of software called dsoal that, when dropped in place of the dsound.dll, can emulate pretty much the full functionality of DirectSound and transfer DS3D API calls to OpenAL.
When paired with an OpenAL driver named OpenAL Soft, which in turn is capable of doing positional audio for headphones with a method called HRTF (head-related transfer function), this setup gives what I think is the best positional audio that's currently possible with a legacy game like PR running on Windows 10. The HRTF I'm using came from publicly available Ircam dataset (IRC 1043 for those who are interested).
Another method to get similar results is to use software called HeSuVi, but on my opinion it doesn't give as crisp and clear result as dsoal + OpenAL Soft does.
This is an excerpt from my PR Launcher's support info, showing that "hardare" audio is indeed enabled.
Spoiler for \"Support Info\":