Mumble is a voice over IP (VOIP) application primarily designed for use by gamers. Mumble uses a client–server architecture which allows users to talk to each other via the same server. Mumble uses Speex not only as a voice codec, but also for noise reduction and automatic gain control. A Mumble server (Murmur) has a root channel and a hierarchical tree of channels beneath it.

“Low-latency, high-quality voice communication for gamers. Includes game linking, so voice from other players comes from the direction of their characters, and has echo cancellation so the sound from your loudspeakers won't be audible to other players. In-Application Overlay - see who is listening and talking in-game. Positional Audio in games - hear your teammates from the direction they stand in.”