Question / Help 2 PC setup with Elgato, audio transfer, desync

[jedenzet]

Hello!
I recently bought a second PC with Elgato HD60 Pro and i was wondering how to set it up. I'm using OBS on both PC's and i'm transfering a preview from my gaming PC to Elgato which is connected via HDMI from my graphics card to second PC. And the problem is that there's no sound transfered to my streaming PC.
I don't want to use a voicebanana or any virtual cable, i think that there should be a simple solution to send my audio from OBS to that HDMI. Why? I'm using a VST plugin in OBS to mix my mic.
I tried to use Nvidia HDMI as a monitoring device in OBS and it kind of works because both mic and windows audio are being transfered to HDMI but it causes a slight delay which i'm unable to fix.

At first it seems that everything works fine but for some reason it's starting to desync after a while. I'll leave this link for an example https://www.twitch.tv/videos/442781741?t=02h45m02s When you go to the beginning of this VOD or somewhere around 1/3 everything is ok.
Why is that? Why is that happening? Is there a better way to send my OBS audio to that HDMI output? Thanks for your time.

 

[Narcogen]

Preview output does not include sound.

OBS is made to output to a file, to a stream, or to a specific device like a decklink card. It's not made to send output to an HDMI port.

If your computer supports audio out on the HDMI port, you could send preview video there and monitor audio there, and that might work, but I'm not certain they would stay in sync.

Another option would be to use the NDI plugin on both machines and send your audio and video output over your local network.

https://obsproject.com/forum/resources/obs-ndi-newtek-ndi™-integration-into-obs-studio.528/

Keep in mind that the NDI plugin can send either your preview or program video output, together with the audio on Track 1, over your network to another computer.