Help on bringing remote guests to a live audience in a theater

[dogmydog]

Dear OBS community,

I am a OBS user for some time now and I'm a big fan of this project!

I'm doing a event on a theater for 100 people and broadcasting everything live on the internet using OBS.
During this event, I will need to receive remote guests and display them in the big screen for the presential audience. I have tried OBS NINJA and Skype NDI following this guide:

3 FREE WAYS to Live Stream Video Calls Like a Pro

How to broadcast a video conference with remote guests on the cheap: Easy & creative methods for switching between separate webcam feeds manually in OBS or a...

www.youtube.com

My gear is:
Computer Laptop with USB 3.0 port
Blackmagic Intensity Shuttle USB
Canon C100 with HDMI cable (the microphone for the live presenter is connected to this camera via XLR cable and the audio goes into OBS via Intensity)
Very good cable internet connection with 100MB upload dedicated link
A HDMI projector to display the OBS on the big screen so the presential audience can follow what is being broadcasted to the internet.

I am very familiar on doing live streaming of presential events, but I've never tried to put a remote guest on the screen and interact with him on stage.
My problem is:
1) Even if I can put a guest via NDI, if I try to stream back to him my signal, he is going to hear himself talk and get the echo of hell.
2) I have tried to create a google meet or group chat and join with my cellphone, leaving OBS as a third invisible guest to live stream my conversation. However, if I'm on stage on the call, the remote guest will hear himself on my phone mic and again, the echo of hell.

Can anyone suggest me a solution for this? I wanted to try VMIX CALL, but it doesn't support my BMD Intensity shuttle.
Thank you for the attention! Best regards from rio,

 

[ltfacemelter]

Not sure if this will work for your theater setup, but my workaround with this when I have multiple guests on my stream is that I set up a Zoom and a Skype call at the same time. I have the participants put their audio and mic ON and video OFF on Zoom, and then have their mic OFF and video ON in Skype.

For your settings in OBS, use an Audio Output Capture from your computer's default audio speakers to capture the Zoom audio that will come in from your participants. And then use an Audio Input Capture for your own mic to ensure your voice is also broadcasted. Works for me every time and avoids the "echo of hell" haha.