Windows 10 guest has crappy audio with behringer USB audio interface passed through via devices configuration menu (USB device) on Virt-Manager (not IOMMU group, I can’t do that because my system’s IOMMU groupings)
^^ Is this the problem with my audio sounding terrible? Suggestions I’ve seen say to:
-Enable MSI interrupt signaling in Windows (that was suggested for someone with HDMI audio and an NVIDIA card, not what I’m doing, so I don’t know if that’s the right approach)
-Pass through entire USB controller (can’t do that because my IOMMU groupings, unless):
-Would ACS override be appropriate in this case? I’m trying to solve the issue in the simplest, most-relevant-to-the-cause way.
-I’m open to buying a PCI expansion card for USB so I can pass a whole device through, but I want to see what’s causing this, and if I can fix it, first - via software methods.
Various buffer settings/sample rates positively affect the issue but they do not resolve it. It doesn’t appear to be the cause, and before anyone asks: yes I have all the Red-Hat windows guest drivers installed.
And please don’t bother to reply here things such as: Behringer is bad, Windows sucks, or “it works on bare metal,” etc – I know all that already 
– but that’s not what I’m asking.