Audio played on the pc with audio format or with video using NDI Tools works fine: Studio Monitor / Screen Capture HX sounds great. Using Dante Virtual Sound Card on pc.
As soon as Vmix is started, audio and videos sounds fuzzy/oversaturated, and crackly.

Here's a basic description of the equipment routes etc...:

Balcony of church - Dell PC (server quality 12gig video card etc) using Dante Virtual Sound Card, pc connected via cat6 to NDI Netgear 4250 (host), sending signal via 60' of cat6 to rack with NDI Netgear 4250 (Slave), routing L & R cat6 for two Magewell 4k converter boxes one for each monitor, a Tesera Dante unit connected to the Netgear routes audio to speakers and handles all the mic input jacks etc.. basically all the digital to analog conversion via dante setup.

So in order to see video I have to log into the Magewell units and tell them to change source "Vmix" to source "video card name." It sees the video card/local pc as the NDI source. That works fine. So, we can run our church service as a screen capture in order to get the audio to play clean. Video itself has never been a problem. Pushing 4k or lower rez doesn't seem to matter... so I am convinced bandwidth is not the issue for the cable runs and for the Netgears capping off at 1 gig. The Magewells are just routing video to the screens.... not any audio. The problem starts when Vmix is started as my sole source app for church service. I have gone through Vmix settings by myself and with a tech yesterday. We did the latest Vmix update too. He was exploring with me remotely as to what I have tried. He had no idea why this is happening.

Any help would be greatly appreciated...