Right think I've got a solution in place.
I've installed the Audigy 2 above the Vortex 2 and connected a 3.5MM audio cable from the Vortex2 to the Audigy Line In via a splitter cable(more on this in a mo). I've then got the Audigy Line Out running to a 3 in 1 out Audio Splitter along with where I split the Vortex2.
So the audio splitter has Audigy on Input 1 and Vortex2 on Input 2. My speakers then connect to the Output of the audio splitter.
In Windows I've made 3x hardware profiles:
- Original Configuration, both cards are active and I can in software choose my preferred card. Ideal for games that let you pick a soundcard
- EAX, this just has the Audigy 2 active. The AV2 is disabled in device manager
- A3D, this just has the Vortex2 active. The Audigy is disabled in device manager
So I can load which API I'm looking to use on start up or load both
Now I read a downside is the Audigy replaces the A3D.dll file with its own, the Vortex2 cannot use this file. Putting the Vortex2 file in its place causes crashes for the Audigy. To get around this on my desktop I have 2 folders, Audigy A3D and Vortex2 A3D. In these folders is each sound cards A3D.dll file respectively. Also on my desktop is a shortcut to C:\Windows\System with hidden files set to be shown. If booting to a different Hardware Profile (or if on the Original Configuration but changing games to one that needs the other), I simply copy and paste the file required for that card into that shortcut.
I tested it and indeed only the enabled card gives audio or whichever is selected on the Original Configuration. I loaded up Thief on my EAX boot with the Audigy as this game I previously played with A3D and got the splash screen, this time no splash screen but EAX was working and it sounded great! Maybe a bit too much reverb but the general 3D positioning was decent.
Only issue I've encountered is the line is quite noisy so I might move the audio leads away from the power sockets. This was on headphones by the way though I've ordered some Creative T20 Gigaworks II speakers which I'm looking forward to trying 😁
1993:A500
1997:Apricot MS540|P/166|16M|Rage3D 2M
2000:PB 9533|P3/533|128M|Voodoo3 2000 16M
'04:P4/3G|1GB|NVIDIA 5700 256M
'07:AMDX2/3.2Ghz|4GB|8800 GTX
'11:i5 2500k|16G|AMD 7950
'16:i5 6600k|16G|NVIDIA 1080|SB AE-5
'21:5900X|32GB|6800XT|SB AE-5