JACK claimed to give

[Jeff Brown]

When I launch qjackctl, it fails with a "no such file or directory" error.

The first time I installed JACK it asked me whether I wanted to give it realtime permissions. I said yes. I thought that would cause it to create an `audio` group, but I have no such group!

Code: Select all

jeff@jbb-lenovo:~$ groups
jeff adm cdrom sudo dip plugdev lpadmin sambashare
jeff@jbb-lenovo:~$ 

It's never asked about permissions again, even though I've switched between JACK1 and JACK2 many times (see below).

I installed JACK and qjackctl in the course of trying to install SuperCollider, the [url=ttps://github.com/supercollider/supercollider/blob/master/README_LINUX.md]Linux readme file[/url] for which suggests apt-installing a lot of stuff:

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sudo apt install -y build-essential  libsndfile1-dev libasound2-dev libavahi-client-dev libicu-dev libreadline6-dev libfftw3-dev libxt-dev libudev-dev pkg-config
sudo apt install -y libjack-dev   ## OR libjack-jackd2-dev
sudo apt install -y qjackctl
sudo apt install -y qt5-default qt5-qmake qttools5-dev qttools5-dev-tools qtdeclarative5-dev libqt5webkit5-dev qtpositioning5-dev libqt5sensors5-dev libqt5opengl5-dev

I've tried it with libjack-dev or with libjack-jackd2-dev; both fail the same way. (I don't keep more than one of those two installed at a time.)

I use Kubuntu 16.04, on a Lenovo Thinkpad E545.

Thanks for your help!

[Pablo]

Code: Select all

sudo adduser jeff audio

will include you in the audio group. Reboot and check "groups" in a terminal again.

The file not found error doesn't seem a problem with qjackctl itself. How are you setting up
qjackctl? Are you following this tutorial?
http://libremusicproduction.com/article ... arted-jack
It is a strongly recommended reading but you might want to skip to
How do I set up JACK?.

You can also use Cadence to set up jack

You are trying to compile supercollider, is it not there a binary (ready to easy installation) package?. I am not sure about the libjack conflict but try to keep things as simple as possible. You can always try to compile: if it fails, normally some "-dev" package will be missing and the terminal will tell you.

[tnovelli]

Try Cadence, it'll check all your settings.

You can just logout and login after adding the audio group. You basically only need to reboot after installing a kernel.

QJackCtl "Realtime permissions" just adds a -R or -P flag to the jackd command line.
This has no effect unless you're in the audio group.
It works best if you're running a lowlatency kernel; with a good computer+interface you can lower the buffer size to 128, 64, or less without getting xruns.