Hi,
If anyone else has issues getting sound on sonic-pi these are some things I had to do to get it working on an xfce manjaro system
I went down a jack rabbit hole at first and no matter what I did with jack and pulseaudio, I could not get any sound to come out whilst using jack. Although applications including sonic-pi were attempting to play sound.
I then removed pulseaudio and installed pipewire and pipewire-jack which removed previous jack installation.
sonic-pi worked as expected after this 
I then also had to install to pavucontrol manage volume levels and xfce4-volumed-pulse to let volume keys work on my laptop.
I have not managed to get the volume applet back yet in xfce. Any clues?
All Manjaro offical ISOs include jack2 for JACK sound server but it requires some system reconfiguration to be able to start (most Linux distributions are not configured to use realtime scheduling for pro-audio)
pamac install realtime-privileges && sudo gpasswd -a realtime $USER`
But the metapackage manjaro-pipewire to replace PulseAudio and JACK has had better consideration from Manjaro Team. The PKGBUILD includes a script realtime-privileges.sh to automatically install realtime-privileges and add user to realtime group
I have not managed to get the volume applet back yet in xfce. Any clues?
I suggest pamac install xfce4-pulseaudio-plugin to reinstall panel volume control
If you had installed manjaro-pipewire to replace pulseaudiothe package manager would not have required removal of pavucontrol, xfce4-volumed-pulse and xfce4-pulseaudio-plugin
2 Likes
I did have xfce4-pulseaudio-plugin installed.
Your suggestion about my original issue being linked to a permission issue with jack2 makes sense.
It looks as though pipewire might be the better supported solution going forward, so will stick with that option.
Configuration requirements for JACK have been well documented and supported for many years. But some changes have incorporated into new kernels so less reconfiguration is needed
realtime-privileges is a great Arch shortcut for the reconfiguration changes needed for pro-audio.
Other distributions have to take a slightly longer route
The auto-install script was only added to manjaro-pipewire a few months ago and has not been mentioned before
The same script could be used for JACK but the terminal commands do the same thing with less complexity