From my notes when I tested Aureal Vortex AU8820B2 and AU8830: it uses asp4dos.com TSR that doesn't require any presence of xEMM386/V86. It load's settings from vortex.ini placed in Windows directory so it probably needs Windows to configure resources. Under DOS there's no wavetable but FM only and it sounds very shitty. It worked better under Win98 where also wavetable can be used by loading soundfont to RAM.

yes bad fm and need an ini made by windows driver. but what is fasinating about this old driver is that can work on any chipset that has pci slot without any ems! my thoughts are if this driver reversed engineered a lot can be found and made a new better sbemu.

I guess that it use some assistance of specific HW in aureal soundchip so it would't help to other soundcards... Yes it would be nice if author of the driver could put this abandonware on github to let see what magic they did...
Also ymf72x/74x dsdma.exe source would be interesting as it implements its own DPMI server but probably the same is now done with HDPMI/VDPMI...

asp4dos.com is just ~35KB, easy to disassemble. I even started, got as far as parsing parameters but couldnt quickly find any magic happening so gave up. Since its not setting any trapping it must be using DDMA.