Try to work with Komplete Audio 6 and JACK

[carlospj]

Hi everyone!

Firts, sorry for my English! jaja

My OS is Antergos (Arch Linux) and I have Komplete Audio 6 and I'm not capable to make it work with JACK. Antergos detects without problem KA6. I can reproduce videos and audio with KA6 and works perfectly. But with JACK is other storie.

In Connections/Audio tab it not appears nothing and as I understand it, this is where I have to do the connections, have not? Connections only appear in ALSA tab.
In Setup the only thing I did have been change input and output devices to “hw:K6”, althought other option appears too, “hw:K6,0”, I don't know the differences between the two.

If I try to start JACK Audio Connection Kit it appears an error messages (I translated the message because it appears to me in Spanish so maybe it is not entirely correct):

You can't connect to the JACK server as a client
- The global operation failed
- You can't connect to the server
Please check the message window for more information.

This is what Message Window shows (the same, the parts in Spanish are translated):

20:19:09.825 Restart statistics.
20:19:09.826 Changes in ALSA connections.
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=There is no file or directory)
attempt to connect to server failed
20:19:09.948 Changed the ALSA connections graphic.
20:19:12.570 JACK is getting started...
20:19:12.571 /usr/bin/jackd -dalsa -r48000 -p1024 -n2 -D -Chw:K6 -Phw:K6
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=There is no file or directory)
attempt to connect to server failed
jackd 0.125.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn 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 is running in realtime mode, but you are not allowed to use realtime scheduling.
Your system has an audio group, but you are not a member of it.
Please add yourself to the audio group by executing (as root):
usermod -a -G audio (null)
After applying these changes, please re-login in order for them to take effect.
You don't appear to have a sane system configuration. It is very likely that you
encounter xruns. Please apply all the above mentioned changes and start jack again!
20:19:12.694 JACK started with PID=8605.
20:19:12.697 JACK has been stopped
20:19:14.706 You can't connect to the JACK server as a client - The global operation failed - You can't connect to the server
Please check the message window for more information.
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=There is no file or directory)
attempt to connect to server failed
23:22:04.022 JACK is getting started...
23:22:04.023 /usr/bin/jackd -dalsa -r48000 -p1024 -n2 -D -Chw:K6 -Phw:K6
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=There is no file or directory)
attempt to connect to server failed
jackd 0.125.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn 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 is running in realtime mode, but you are not allowed to use realtime scheduling.
Please check your /etc/security/limits.conf for the following line
and correct/add it if necessary:
@audio - rtprio 99
After applying these changes, please re-login in order for them to take effect.
You don't appear to have a sane system configuration. It is very likely that you
encounter xruns. Please apply all the above mentioned changes and start jack again!
23:22:04.143 JACK started with PID=9161.
23:22:04.146 JACK has been stopped
23:22:06.183 You can't connect to the JACK server as a client - The global operation failed - You can't connect to the server
Please check the message window for more information.
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=There is no file or directory)
attempt to connect to server failed

Any idea to solve this?

Regards.

[asbak]

To start with, you didn't configure some prerequisites on your system so performance is already suboptimal.

The logs tell you:

Please add yourself to the audio group by executing (as root):

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usermod -a -G audio <your-username>

You should also adjust the limits.conf file (or whatever equivalent Arch uses) as is suggested in the logs for better performance.

"Please check your /etc/security/limits.conf for the following line
and correct/add it if necessary:
@audio - rtprio 99"

Once this is done, reboot the computer and then move to the next steps.


Make a note of the name of your audio device, confirm it matches what you are currently using (K6).

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aplay -l

Ensure pulseaudio is not running

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ps -ef | grep pulse

If it is you will have to configure it to NOT autospawn, and then you will have to stop it

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pulseaudio --kill

Check again to ensure pulseaudio is not running

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ps -ef | grep pulse

Once you are certain pulseaudio is not running you proceed to the next step.
Search for any running jack and jackdbus processes. Make sure you kill them completely with kill -9

Repeat this process until you are sure no jack processes are running.

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ps -ef | grep jack

Once you have successfully passed this checkpoint, proceed to start jack using the example below:

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jackd -dalsa -r44100 -p512 -n3 -D -Chw:K6 -Phw:K6

[carlospj]

Hi asbak.

Adding my user to audio group and adding to limits.conf what the log recommended, I've got to start JACK without errors and now in Connections/Audio appears the system connections. With this, the guitar sounds clean.

I follow the next commands but I stop because I'm not sure that pulseaudio is not running.
When I introduce:

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ps -ef | grep pulse

the terminal returns this:

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carlospj  1878   701  0 19:29 ?        00:00:00 /usr/bin/pulseaudio --daemonize=no
carlospj  1935  1788  0 19:35 pts/0    00:00:00 grep pulse

If I use pulseaudio --kill command and then write again ps -ef | grep pulse, the answer is the same that before but I'm not sure what is meant exactly so I prefer to wait for your answer.

One more thing. When you say "Search for any running jack and jackdbus processes. Make sure you kill them completely with kill -9", what do you mean with this?

Thank you very much.

Regards.

[asbak]

Ola Carlos

I think your system may still be set to autospawn (automatically restart) pulseaudio. You need to change this setting so that pulseaudio will stay shut down once you have stopped it. (Internet will have information on where to configure this.)

That is why, even when you stop pulseaudio, it still shows pulseaudio processes. (You don't really want to have any pulseaudio processes running when using jack. Some guys use both at the same time but it is a more advanced topic. For now, better to use either pulseaudio or jack at one time.)

The reference to running jackdbus processes is with regards to this running in the background. Sometimes jack stops working properly and you stop it (for example using qjackctl front end or on the command line) but still it won't work properly. This is because jackdbus is running which hijacks (no pun intended) jack. Unless jackdbus is stopped completely, jack may not work properly.

I got rid of jackdbus by compiling jack without jackdbus support but this is a more advanced topic. For now just be aware that jackdbus can cause you issues so make sure that you stop both jack and that jackdbus process has also been killed, before starting jack again.

Now that you have your card working, another thing you can do is to reduce the latency of the card. At the moment it will be a bit "slow" (there will be some delay in the signal) which you can reduce by changing the "p" value to 128, like the example below.

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jackd -dalsa -r44100 -p128 -n3 -D -Chw:K6 -Phw:K6

Be aware that your system is possibly still not really tuned for audio, you need to use a low-latency kernel (to reduce xruns) and you need to run jack with a high priority. Anyway, those are more advanced topics, the Arch community should have information available for you to tune your system better.

[carlospj]

Sorry, it's been a while. I haven't do anything since the last time we spoke. I've been very very busy and I've had no time at all to do anything related with this.
This weekend maybe I have some time to put me to work with this. When I'll try something with this issue, I'll post the results.

Regards.