Mumble is low latency voice chat client/server program with clients available on all platform. I tried: Mumble for iOS on the iPhone, works good, Mumla on Android (doesn't work on Android 5 and works good on Android 8) and the desktop linux client, works good.

To be more precise, I installed murmur-server on Debian Buster, like this:

sudo apt-get install mumble-server
sudo systemctl stop mumble-server

mumble-server starts after installing the package with apt, I stop it because I want to have the configuration in my user account.

Run murmur-user-wrapper to create the default config:

murmur-user-wrapper -i

Edit config file located in:

~/murmur/murmur.ini

Set the server password after serverpassword=passExample.

Then set password for the SuperUser (SuperUser is root for the mumble-server):

murmur-user-wrapper -p aRandomPassword

Start the server with:

murmur-user-wrapper

My local network is behind a router, to make the mumble-server reachable from the internet I add a configuration in the router. murmur-server uses port 64738 by default, so I forward port 64738 to the machine running murmur-server in the router.

Start the client and connect with SuperUser to let regular users register their username:

Right click Root
>> Edit
>> ACL
>> Enable Register Self for all

The regular users enter their username in the client and type the serverpassword (passExample) as password.