Problem with Jack and QjackCtrl

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rxscabin
Posts: 2
Joined: Sat Jan 24, 2015 7:21 pm

Problem with Jack and QjackCtrl

Post by rxscabin »

Like an idiot I started messing around with something that was working OK and now it does not work. I changed the options in QjackCtrl to maximize the performance for use with my Sacrlett 2i2. I changed backe to the saved default preset and this is what I get:
14:17:56.989 Patchbay activated.
14:17:57.003 Statistics reset.
14:17:57.013 ALSA connection change.
14:17:57.022 D-BUS: Service is available (org.jackaudio.service aka jackdbus).
Cannot connect to server socket err = No such file or directory
Cannot connect to server socket
jack server is not running or cannot be started
14:17:57.033 ALSA connection graph change.
14:17:57.230 ALSA active patchbay scan...
14:18:04.702 D-BUS: JACK server could not be started. Sorry
Cannot connect to server socket err = No such file or directory
Cannot connect to server socket
jack server is not running or cannot be started
Sat Jan 24 14:18:04 2015: Starting jack server...
Sat Jan 24 14:18:04 2015: JACK server starting in realtime mode with priority 10
Sat Jan 24 14:18:04 2015: control device hw:0
Sat Jan 24 14:18:04 2015: control device hw:1
Sat Jan 24 14:18:04 2015: [1m[31mERROR: Failed to acquire device name : Audio0 error : Cannot allocate memory[0m
Sat Jan 24 14:18:04 2015: [1m[31mERROR: Audio device hw:0 cannot be acquired...[0m
Sat Jan 24 14:18:04 2015: [1m[31mERROR: Cannot initialize driver[0m
Sat Jan 24 14:18:04 2015: [1m[31mERROR: JackServer::Open() failed with -1[0m
Sat Jan 24 14:18:04 2015: [1m[31mERROR: Failed to open server[0m
Sat Jan 24 14:18:06 2015: Saving settings to "/home/rxscabin/.config/jack/conf.xml" ...
14:18:17.601 Could not connect to JACK server as client. - Overall operation failed. - Unable to connect to server. Please check the messages window for more info.
Cannot connect to server socket err = No such file or directory
Cannot connect to server socket
jack server is not running or cannot be started
Can anyone help me? I am using Ununtu Studio 12.04 Thank you for your help.
Pablo
Established Member
Posts: 1274
Joined: Thu Apr 17, 2008 9:57 pm
Been thanked: 3 times

Re: Problem with Jack and QjackCtrl

Post by Pablo »

Using presets and names is not recommended for new users of qjackctl. It's more hassle than it's worth :D

What is the terminal output of

Code: Select all

cat /home/rxscabin/.config/jack/conf.xml /proc/asound/cards && arecord -l && aplay -l
?

This tutorial is gold:

http://libremusicproduction.com/article ... arted-jack
rxscabin
Posts: 2
Joined: Sat Jan 24, 2015 7:21 pm

Re: Problem with Jack and QjackCtrl

Post by rxscabin »

Thank you for your quick reply. Strangely, when I turned the computer back on, it worked. However, I would like to avoid having problems in the future and get good/better. Here is the output:
<jack>
<engine>
<option name="driver">alsa</option>
<option name="realtime">true</option>
<option name="verbose">false</option>
<option name="client-timeout">500</option>
</engine>
<drivers>
<driver name="netone">
</driver>
<driver name="dummy">
</driver>
<driver name="net">
</driver>
<driver name="alsa">
<option name="device">hw:0</option>
<option name="rate">44100</option>
<option name="period">32</option>
<option name="nperiods">2</option>
<option name="hwmon">false</option>
<option name="hwmeter">false</option>
<option name="duplex">true</option>
<option name="softmode">false</option>
<option name="monitor">false</option>
<option name="dither">n</option>
<option name="shorts">false</option>
</driver>
<driver name="loopback">
</driver>
<driver name="firewire">
</driver>
</drivers>
<internals>
<internal name="netmanager">
</internal>
<internal name="profiler">
</internal>
<internal name="audioadapter">
</internal>
<internal name="netadapter">
</internal>
</internals>
</jack>
0 [SB ]: HDA-Intel - HDA ATI SB
HDA ATI SB at 0xfe7f4000 irq 16
1 [USB ]: USB-Audio - Scarlett 2i2 USB
Focusrite Scarlett 2i2 USB at usb-0000:00:13.2-1, high speed
2 [HDMI ]: HDA-Intel - HDA ATI HDMI
HDA ATI HDMI at 0xfe9f4000 irq 19
**** List of CAPTURE Hardware Devices ****
card 0: SB [HDA ATI SB], device 0: ALC892 Analog [ALC892 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: SB [HDA ATI SB], device 2: ALC892 Analog [ALC892 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: USB [Scarlett 2i2 USB], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
**** List of PLAYBACK Hardware Devices ****
card 0: SB [HDA ATI SB], device 0: ALC892 Analog [ALC892 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: SB [HDA ATI SB], device 1: ALC892 Digital [ALC892 Digital]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: USB [Scarlett 2i2 USB], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 2: HDMI [HDA ATI HDMI], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
Thank you again. That tutorial looks good and helpful. There are next to no good Jack tutorials.
Pablo
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Posts: 1274
Joined: Thu Apr 17, 2008 9:57 pm
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Re: Problem with Jack and QjackCtrl

Post by Pablo »

There are a couple of things that don't seem right.

First, the audio interface. Use the little horizontal arrow on the right of the interface field to select the Scarlett.

32 frames / period do bad things. You might think that less latency is better, when it is not. More latency is better for perfomance.

You only need low latency when you play live through the computer (known as "software monitoring", in contrast, in direct monitoring from the Scarlett you already have zero latency and you don't need very low latency in jack). This is because you don't want to notice the latency. To test playing live with software monitoring (I am thinking guitar but you didn't say anything about what you want to do, I am trying to guess): Decrease the frames /period value, starting from 1024 step by step. 1024 is too much for playing live. If you notice latency with 512, decrease to 256. How does it feel? Is it 128 better? Below 128 for guitar is unnecesary for me at least, as a rule of thumb. 64 is very risky, 32 is a suicide. You don't want xruns, aka, red numbers, so increase the latency when/if your ears can bear it.

By the way, what is the output of

ulimit -r -l

?

I ask because there is a basic configuration that you can't miss and the above informative command tells if that configuration is right or not
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