Mumble is a free, low-latency voice chat program designed for gaming. Knifeback's Mumble server is hosted at kbm.davejk.net port 65432.

You can register your Mumble username by right-clicking yourself in the user list and choosing register. This will reserve your name (so nobody else can use it) and allow you to create channels (by right-clicking root and choosing add).

You can use Mumble for anything you want, not just Knifeback-specific activities. However, please don't deliberately disrupt games in progress.