User:Crantila/FSC/SoundServers/JACK

What JACK Is, and Why It Exists

(no algorithms)

Knowing When to Use JACK

(no algorithms)

How to Setup Your System for JACK

• must refer to kernel/system optimization section
• by default, in Fedora, when JACK is started, it receives control of the audio devices from PulseAudio. No PA device works until JACK quits

Installation

1. run 'yum install jack-audio-connection-kit qjackctl' (this installs JACK and a GUI application to control it, QjackCtl)
2. Approve the installation.

Safely Enable Real-Time Scheduling

1. Add yourself, and anybody who uses JACK, to the 'audio' group (instructions for this are probably in an existing Fedora Doc)
2. Planet CCRMA's version of JACK automatically enables real-time priorities. To make it safer, edit '/etc/security/limits.conf' so that the final lines read:

   @audio - rtprio 99
   @audio - memlock 4194304
   @audio - nice -10

3. If you are not using PlanetCCRMA's JACK version, then write those lines in!

Starting and Stopping

1. Run QjackCtl from the KMenu or Applications menu
2. to start JACK, press "Start"; to stop it press "Stop"
3. Use the "Messages" button to see messages, usually errors or warnings
4. Use the "Status" button to see various statistics

Adjusting Settings

1. Press the "Setup" button
2. Run 'cat /proc/asound/cards' to see a list of sound cards in your system, and choose the one you want by name
3. Put (for example) 'hw:SB' in the "Interface" field (this is more robust, etc.)
4. Adjust the sample rate no higher than the highest supported by your interface; 44100 is CD quality; 48000 is probably sufficient for most uses
5. Go to the 'Options' tab, and deselect "Execute script on Startup: artsshell -q terminate", since it's not needed in KDE4 or GNOME

Controlling JACK with QjackCtl

I should probably put this stuff in its own section.

Also, be sure to cover the "patch bay," which is a method to save a series of connections.