Mumble 

Mumble is a free, open source, low latency, high quality voice chat application. Mumble created the first VoIP application to establish true, low-latency voice communications more than a decade ago. But low latency and gaming aren't there only shining aspects. 

There are people who use our products to recording podcasts with our multichannel audio recorder, gamers seeking realism with our positional audio in games, Eve Online players with huge communities, sometimes over the 100 simultaneous voice participants (they make good use of our extensive permission system), the competitive Team Fortress 2 community, hobby radio streaming users and workplaces that are adapting mumble to their needs, whether you need some communication for yourself, connecting country’s or airplanes

Administrators appreciate Mumble for being able to host themselves and that they have control over data security and privacy. Some people make use of the extensive permission system in case of complex scenarios, for example a leader can split two groups and is the only one who can speak in both groups. There are others who love to provide their users with additional functionality, like scrips that use the server’s API, music bots hosting or others who like to connect to the server. 
Those who have an existing user database often use authenticators to allow authentication with the existing account login details.

Features

There are several features in Mumble, every feature suits a user, there are three types of users. These groups are interested in different capabilities. We will show you the three types of users and their features.

Features for End-Users:

• Private and secure – encrypted communication and private key authentication.
• Low-latency – easy for gaming and talking.
• You recognize friends across the servers.
• There are bots who guide you through setup, like configuring your microphone. 
• In gaming:
  •  you can see who is talking, current time and the FPS (frames per second)
  • You hear the players from the location in game

Features for Administrators:

• Libre Sorfware – no problems with licensing, caveats and limitations.
• Open Source – based on technology, security and extensibility.
• User permission system for extensive (ACL).
• Four possible extensible through ICE-protocol.
  • Channel viewers
  • Web interfaces 
  • Authentication
  • Custom chat commands 

Features for Hosting users:

• Free software – no license or costs.
• Administration goes automatic through ICE-middle ware.
• Resource costs are low.
• Server software is stable.
• A choice between official and other server software.
• Custom web-interfaces.
• It is possible to gain access to channel viewer without giving control away.