VTech Laser 128.

But that’s just an Apple II clone.

I don’t have any experience with virtual surround, but I do have a potential alternative if you don’t get it figured out.

If the games you play have a headphone mode, try it. That typically gets a pretty good virtual surround effect. As for improving sound quality, check out the AutoEQ project on GitHub. I got some cheap $20 Monoprice headphones that sound like they’re $150 or better when using the correct profile from AutoEQ.

I used dalnet around 2000 or so. Hung out in #speaker’s_corner quite a bit.