Tonight I noticed something peculiar that may explain why some users still have trouble starting JACK or running it in real time without xruns even after following all the basic configuration steps. I’m not sure if this is specific to Ubuntu but it has to do with the users-admin tool in Gnome. The graphical tool is misleading because if one were to try to add a user to the audio group by clicking the “Manage Groups” button, one might notice the audio group does not appear in this list and one might feel compelled to create it (as I did). What is not immediately evident is that the audio group already exists, and adding it a second time will change its group number to something like 1001, thereby preventing applications from directly accessing the audio hardware. If you’ve tried to add the audio group using System > Administration > Users and Groups, take a look in your /etc/group file. The group number for audio should normally be 29. If you don’t see your username listed as a member of audio, add yourself using this command:
useradd -G audio yourusername
I had always just assumed my laptop’s cheap integrated sound card wasn’t up for the task, but after making this correction I can run Ardour and JACK in realtime with 256 Frames/Period. Lesson learned: It’s a good idea to use the terminal for administrative tasks.
from: http://ardour.org/node/2062
Troubles running qjackctl in realtime?
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Re: Troubles running qjackctl in realtime?
It doesn't warn you when creating multiple groups with the same name? That's crap .studio32 wrote:if one were to try to add a user to the audio group by clicking the “Manage Groups” button, one might notice the audio group does not appear in this list and one might feel compelled to create it (as I did)
Re: Troubles running qjackctl in realtime?
good job!raboof wrote:I added a check for this situation to the quickscan