INTEGRATE JACK WITH PULSEAUDIO The original text is placed at: http://www.harald-hoyer.de/linux/pulseaudio-and-jackd Switch to root account. Install the required packages: yum install pulseaudio-module-jack alsa-plugins-jack jack-audio-connection-kit Add yourself to the pulse-rt and jackuser groups. usermod -a -G pulse-rt,jackaudio "" Check /etc/security/limits.conf (our package should provide these changes): @jackuser - rtprio 20 @jackuser - memlock 4194304 @pulse-rt - rtprio 20 @pulse-rt - nice -20 Switch to your normal user account. Create ~/bin subdirectory if absent: mkdir -p ~/bin Copy the pulseaudio start file: cp /usr/share/doc/jack-audio-connection-kit-*/jack-audio-connection-kit.pa ~/bin/jack.pa chmod 755 ~/bin/jack.pa Close all your sessions and relogin to get the new group permissions and limits. Kill the current pulseaudio daemon: killall pulseaudio Start the jack daemon (your parameters may be different): jackd -R -P4 -dalsa -r44100 -p512 -n4 -D -Chw:0 -Phw:0 Start the pulseaudio daemon: pulseaudio -nF ~/bin/jack.pa Now everything should work. Next chapter describes steps for older Fedora vesions. RUNNING JACK SERVER IN REALTIME MODE The JACK server jackd has the capability to run in a real-time mode which greatly decreases the chance of audio glitches. The real-time mode is enabled by passing the -R or --realtime option to jackd when starting the server. It is only possible to run jackd in real-time mode as a non-root user by modifying your PAM configuration, PAM stands for Pluggable Authentication Modules and is the primary authentification mechanism used on Fedora. The primary source of PAM documentation can be found at the following at http://www.kernel.org/pub/linux/libs/pam/ The specific PAM configuration file that needs to be modified is /etc/security/limits.conf and it controls the system resource limits. It is important to understand that modifying the resource limits configuration files can decrease the security of your system. Documentation specific to the resource limits PAM module can be found at http://www.kernel.org/pub/linux/libs/pam/Linux-PAM-html/pam-6.html#ss6.12 The resource limits that need to be changed to allow jackd to run in realtime mode are named rtprio and memlock. To increase the limits for a specific user named fred you would add the following to /etc/security/limits.conf fred - rtprio 20 fred - memlock 50000 The value of rtprio can be set in the range 0 - 99 where any value greater that 0 will allow the user to change the scheduling policy to "real-time". By default the JACK server requires a minimum rtprio setting of 20 but jackd will accept a command line parameter -P or --realtime-priority which will change the minimum required value of rtprio that is needed, but the default of 20 is nearly always sufficient. The appropriate value for memlock is dependent on the amount of memory present in the system but a minimum value of 50000(50MB) and a maximum value of half the available memory can be used as a rough guideline. To verify that the resource limits have been modified you can use the bash built-in ulimit command, for example: $ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited max nice (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 8191 max locked memory (kbytes, -l) 50000 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 max rt priority (-r) 20 stack size (kbytes, -s) 10240 cpu time (seconds, -t) unlimited max user processes (-u) 8191 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited file locks (-x) unlimited Keep in mind that you may have to re-login before changes to limits.conf take effect.