Echo in meeting with Zoom Room when using Rodecaster

[matiasts]

Hi,

We recently made our own setup for the sort of Town Hall meetings.

We have a Rodecaster Duo, 2 wireless mics of the same brand a Logitech Rally camera, and a speaker. We are using a Zoom Room license that runs on a Mac Mini and an iPad as the controller. 

The setup work overall okay except that there is one meeting, yes one in particular, where people that are connected remotely have echo when they talk. Interestingly, we have another meeting using the same devices and setup where there is no echo. 

Some of the things that I noticed are:

1. The meeting with echo the first couple of folks that join remotely don't seem to experiment echo from the beginning. 
2. Once the meeting that has echo finish I have asked a few folks to stay and they don't have echo.
3. There is a Neat bar that connects remotely to both meetings and one of the meetings they have echo and the other one they don't
4. The number of people joining to the meeting with echo is bigger (30) than the other one (20)
5. The controller has the audio and video that corresponds to the right devices
6. We have setup some custom values for the outputs of the Rodecaster Duo. Where we basically increase the volume of the mics and the volume of the zoom for people that is connected remotely using the virtual output.
7. The meetings configuration when I look at Zoom are similar one to the other one. However, whenever the meeting with echo starts the camera doesn't turn on by itself. Wondering if the Rally camera is using a mic here and how to check that though with point 1 and 2 echo should be constant.
8. People that is connected remotely doesn't hear the echo when the location with the setup talk through the mic.
9. People that is connected remotely have been all mute except for the meeting room using the Neat Bar though point 3 makes me think that it shouldn't be a problem that device.
10. To stop the echo muting the room with the Rodecaster is enough.

Curious if anyone experienced anything like this or if you have a way to fix the problem or keep troubleshooting. Also, if you have tips to work around this problem in the meantime that could be helpful as the communication isn't full duplex someone has to mute our room to stop the echo. As there are too many people is hard to troubleshoot when all are on the call. 

[storyhub]

You are trying to do a very complex audio setup. If you are using speakers for a local live audience so they can hear Zoom participants - that is an echo feedback source. Echo is delayed feedback and typically comes from sound out from a speaker feeding back into a mic (that can be local or from any participant having speakers on) or not using a proper mix-minus when mixing all the sound sources. Most likely based upon your comments the feedback is coming from the speaker in the local room. Local sound must have isolation between the mics and the speakers. Each time you open another mic you must lower all mics by 3db. For isolation all mics need to be behind the speakers and the speakers need to be kept as low as possible. If you are using the rodecaster Duo to feed Zoom participant audio to speakers it does NOT have mix-minus capability. Since the Neat bar is probably at the screen then the mics are in front of the speaker and are picking up participant audio. If you insist on using multiple omni-directional mics then consider providing earpieces for listening rather than using a speaker. Yes there are technologies that can mic everyone in a room with a speaker, but it is beyond most peoples budget since it is in the $5000+ range. What you are attempting to do is very complicated and you might want to consult a specialized engineer (and yes I too am an engineer specialized in A/V and broadcasting).

[matiasts]

thanks, @storyhub for the answer.

I'll try to find an A/V engineer who can help us with this. 

I'm curious about your opinion if this is something that can be tackled using the noise gate and/or the high pass filter that the Rodecaster Duo configuration brings. 

Thanks again.