Disroot's Audio is powered by Mumble. Mumble is a free, open source, low latency, high quality voice chat application. It was originally intended for gamers, but it can be use to organize audio meeting, conference, etc.
You don't need any account to use Mumble. But you have more rights if you register your username.
Disroot Mumble: mumble.disroot.org
Project homepage: https://www.mumble.info
Source code: https://github.com/mumble-voip/mumble
Mumble's features highlights:
Use your favorite Mumble client
There are clients on desktop/web/mobile.
Easy to use
Download the Mumble app available on your device (desktop, Android or iOS), connect to mumble.disroot.org and you can already start creating an audio channel and talk to people!
Great audio quality
Low-latency and noise suppression, so it is great for talking. You can have about 100 simultaneous participants!
Private and secure
Communications are encrypted, and authentication is by public/private-key by default. If you use the Desktop Mumble software, you can give very specific permissions to your channels, groups and users.
Manage your project on the go with Android mobile app (available on F-Droid) or iOS app.