vrCAVE Standalone With Voice Chat
While vrcave does not support voice chat in our game, we have some alternatives that work for Vive focus 3, vision, and Pico.
This guide will assume a fully installed and operational vrcave setup.
Go to F-droid to download Mumla (don’t download F-Droid)
Copy the downloaded APK to your headset. I copied it to the Downloads folder for Pico and Vive Focus headsets.
put on the headset and locate the recently copied AP.
For Pico
Go to File manager, and select APKs. then open the APK to begin installing it. Once installed, Mumla will be available in the App Library. 
For Vive
In the headset, go to settings, advanced settings, and enable “allow apps from unknown sources”
Go to settings->Storage->File-Browser->Downloads. open the APK to begin installing it.
Once installed, it can be found in the Library, but only under 2D Apps category
You will also want a mumble server, the setup guide for mumble is here: all you need to do is follow the setup steps for the server PC: https://vrcave.github.io/operationGuide/mic_chat_mumble.html
Setting up a static IP for your server PC is important so that the headsets can join the mumble server.
In mumla, want to accept certificate generation, and connect to a server.
Click the + on the top right of mumla to connect to a server. Name your server whatever you want, input the server PC IP address, and then a username, the username cannot have any spaces in it. Or it will refuse to connect.
Do this for each headset, the voicechat will stay active when you minimize the mumla app and start up vrcave.