We use YUAN SC542 N4 HDMI capture card and two Sony cameras connected through HDMI to the capture card.

Each camera has lapel microphone connected to one the camera inputs (XLR).

This means, that audio from each microphone comes through separate HDMI input channel (along with video)

All the stuff located in some relatively small room (like 20 sq.m.)

Now, when we try to set up whole thing we face up issue, that each microphone hear not solely guy it connected to, but also another guy, which have his own microphone.

Let's imagine, that both guys are on air, and both microphones are active.

As consequence, we get terrible audio scene with voice of the talking speaker coming from his own microphone and then voice of the same speaker coming from another microphone, but with slight delay.

I can imagine, that such a question was asked at least hundred times here. However my attempt to find proper solution here was not succesfull. Thus any help - how to fix/solve this would be highly appreciated!