newbie question about JACK

[akioshin]

how to start jack? when i start qjackctl it gives me this error

22:47:49.283 Patchbay deactivated.
22:47:49.284 Statistics reset.
22:47:49.285 Could not open ALSA sequencer as a client. ALSA MIDI patchbay will be not available.
ALSA lib seq_hw.c:457:(snd_seq_hw_open) open /dev/snd/seq failed: No such file or directory
22:47:51.382 Startup script...
22:47:51.383 artsshell -q terminate
sh: artsshell: command not found
22:47:51.785 Startup script terminated with exit status=32512.
22:47:51.785 JACK is starting...
22:47:51.785 /usr/bin/jackd -R -dalsa -dhw:0 -r48000 -p1024 -n2
22:47:51.789 JACK was started with PID=7246.
jackd 0.116.1
Copyright 2001-2005 Paul Davis and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
cannot use real-time scheduling (FIFO at priority 10) [for thread -1207593280, from thread -1207593280] (1: Operation not permitted)
cannot create engine
22:47:51.805 JACK was stopped successfully.
22:47:51.805 Post-shutdown script...
22:47:51.806 killall jackd
jackd: no process killed
22:47:52.216 Post-shutdown script terminated with exit status=256.
22:47:53.844 Could not connect to JACK server as client. - Overall operation failed. - Unable to connect to server. Please check the messages window for more info.

[Pablo]

Hi akioshin,

You are trying to start jack with the "realtime" option but you (as a user) don't have the realtime priority.
Either you do without the realtime option or (better) add yourself to the audio group by doing a (I am guessing here, are you in ubuntu or similar?):

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sudo adduser akioshin audio

(or whatever you user login name is)

And then edit, also as superuser, the /etc/security/limits.conf file and add the realtime priority, the memlock parameter an by the by the nice priority as shown in the wiki, system configuration.

These changes need a computer reboot to take effect.

Cheers! Pablo

EDIT: By the way, the previous post deals with exactly the same problem. Use search , read the wiki...

[akioshin]

i'm using fedora 11 as my distro and

i was searching for the keyword JACK and nothing came up so i just posted it,and miss the similar post but i'll keep that in mind

[Pablo]

Sorry if I have been a bit rude. check the wiki, anyway. I said ubuntu, because it is what I know. However, the wiki should be distro neutral and the basics (add yourself to the audio group, set the realtime priority as 90 or 99 and the max locked memory size as unlimited or a high value) are the same, although the exact commands could be a little different. You can check if you belong to the audio group by doing 'groups' in a terminal and you can check the secutiry limits configuration with 'ulimit -a'. This should work for any distro, afaik.

I hope this helps, regards, Pablo

[raboof]

cannot use real-time scheduling (FIFO at priority 10) [for thread -1207593280, from thread -1207593280] (1: Operation not permitted)

See also: http://trac.jackaudio.org/wiki/Troubleshooting

Let us know if that's too short for you, so we can improve those docs.

[akioshin]

thanks for the reply guys

@pablo no worries it is ok hehehe

i created a new user and put in in audio group, configured the limits.conf and restarted my system
and somehow it works but sometimes it won't, like when i start my qjackctl it gives me the same error
and a friend of mine told me to turn off my pulseaudio

how can i turn off the pulseaudio and can i turn it back on?

i know i ask to many questions, this is my first time doing multimedia stuff in linux i usually do it on windows
but i really eager to learn this, thanks for understanding

[studio32]

In general you should close all other (sound) applications/sources (youtube for example) before you start Qjackctl.

If pulseaudio is the problem you can start qjackctl in terminal with

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$pasuspender qjackctl

Also another good tip is to run the script you find in our WIKI system configuration