There's an alternative a3d.dll floating around the net you can use instead of the one that comes with A3D-Live, A3Dx5, supposedly developed by Creative. The latest version I found (220.127.116.11) is included with older unofficial patches for Interstate '76 Nitro Pack because it solves a critical sound bug with that game (I also added it in my own I76 Patch in A3D folder).
The instructions there say to install A3D-Live, then replace a3d.dll with an alternative one, (A3Dx5) and the older version of it (18.104.22.168) is also at linked at PCGW. That page says to install A2D drivers (A3D 2? - a2ddrivers312.exe) first then use a3dx5 or A3D-Live. A2D drivers and A3D-Live are hosted on the same russian website.
a2ddrivers312.exe package only has a3dapi.dll. Somewhere else, I found a3ddrivers312.exe, which also has a3d.dll and a3d.vxd, the latter is definitely Windows 9x driver. It seems both a2ddrivers and a3ddrivers can be ignored when it comes to modern OS, so install A3D-Live, then find references in registry under HKEY_CLASSES_ROOT with an absolute path to a3d.dll, change it to just say a3d.dll so you can put and use the alternative a3d.dll in particular game's folder if it works better with it. Or is there better way? I'm a bit lost when it comes to A3D stuff.
Another A3D wrapper (a3d.dll) one may come across goes by the name of QSound.
Is there a reason to use A3D mode if the particular game has good DirectSound backend? All those wrappers use DirectSound internally.