A little update:
After using Voicemeeter Banana forever, and just putting up with the tiny but noticeable lag between an effect happening and feeling it (output), I finally got serious about trying to get an ASIO working to give me real 5.1 effects, and not just stereo (left/right). Long story short, if you have Realtek motherboard audio, there’s probably not an ASIO driver from Realtek that actually works.
However I revisited ASIO4ALL (probably the 3rd time I’ve tried to set it up), and finally figured out how to make it work. Maybe I’m the dumbest kid on the block, but I just didn’t get it. Install it, start Simshaker, then in the ASIO4ALL pop up, select your audio output. That’s it, it will work; I was making it too complicated.
Now, after uninstalling VoiceMeeter, abandoning my second USB sound card, hooking up my audio cables to the motherboard outputs for speaker, rear and center, I’ve got 4 separate audio channels for feedback.
And Simshaker knows what to do with them! It’s very nice, and effects are properly directed based on the origin of the feedback.
The best part is, and the reason I wanted to figure it out in the first place, is no perceptible lag! None. You fire guns, or touch down, and the feedback is instant.