JACK stands for JACK Audio Connection Kit. It is a audio server and it has two main features :
- It allows different audio applications to communicate with each other (for instance, the user can route the output of Pure Data into Ardour to record it),
- It makes it possible to reduce latency while running Pd by harnessing the real-time capabilities of the operating system.
JACK is just as essential to my setup that my low-latency OS (currently Ubuntu 10.04).
Although JACK is actually just a sound server with no GUI, a very handy user front-end exists. It’s called Qjackctl, and it looks like this :
This interface allows the user to have full control over the JACK server, including :
- Input and output settings (soundcard…),
- Audio settings (samplerate, buffer size and latency…),
- Real-time scheduling.
The user can also control the connections between different audio applications. This can get crazy (JACK is really a very powerful piece of software), though I have never connected more that two apps.
Installing JACK was pretty easy on most Linux distros i’ve tried, though it sometimes required editing a configuration file and adding myself to some groups. I suggest reading the FAQ and the numerous tutorials available on the internet (try this if you’re using Ubuntu).