JACK

If you have any experience with traditional professional audio hardware (synthesizers, effects, mixers) or even professional networking gear (routers, switches, vlans), then you are accustomed to the notion that signals must be routed from one place, through a filter of some sort, to a target, and then perhaps through another filter, and then a final destination.

Patchbay by Pinnacle_College on Flickr.

JACK is an application that, once started, runs in the background and routes audio.

There are three varieties of audio applications on Linux:

• Those that do not and cannot use JACK (ie, it has not been programmed to use be “JACK-aware”). Usually consumer applications.
• Those in which JACK is optional.
• Those that require JACK in order to run.

Depending on what applications you want to use, you may or may not ever need JACK. It's not a bad thing to have available and isn't terribly big, so it is a recommended application for a Slackermedia system, but whether or not you use it daily or just once a year depends on what you do with your computer.

There are two concurrently supported versions of JACK.