Using Jack
A lot of people have struggled with Jack, often it is packaged with other programs and it doesn't like some hardware. I have taken the opposite approach, to break it down into small pieces.
Why Jack?
Jack controls the flow of sound between programs and hardware. It is useful if you are making music and/or recording sound. For example, sometimes when recording you may notice glitches. Jack will tell you when your computer has failed to record a signal - this saves having to check the recording by ear.
Two Jacks?
Yep, currently there is Jack 1 (v0.*) and Jack 2 (v1.*) both under active development - neither supersedes the other, but I found Jack 1 to be more compatible with ALSA.
GUI and backend
In addition to two versions of Jack, there is a GUI program for easy setup of jack known as qjackctl. (often one of the two backends is packaged with qjackctl).
Installation
Setting up jack
Start qjackctl from the multimedia menu. This is a game, try to get the lowest latency without your system returning errors.
1. click on 'set up'-
Tick realtime, reduce Frames/Period to 128, increase timeout to 5000. Select input and output devices.
2. click on 'misc' tab, select 'Start Jack on app startup' and 'enable system tray'. Click okay.
3. Click the 'start button', if no errors are returned close window. If errors are returned click on messages and diagnose. If you are getting xrun errors return to 'set up' and increase 'Frames/Period'.
4. If your audio programs are running and/or your recording and xruns pop up, again return to 'set up' and try increasing 'Frames/Period'.
(btw I've set jack to run at a nice of -20 so it hogs the os)
Compatibility
It would be useful if people report what systems they have got jack working on and which don't work. Please comment below.
