Linux: Easy user experience by routing JACK through PulseAudio

[SebiderSushi]

Hello. I've always had trouble making my first steps with Sonic Pi because i constantly ran into issues of JACK clashing with PulseAudio.

Today i wrote a script that launches sonic pi and routes its audio through PulseAudio using the pulseaudio-module-jack:
https://github.com/SebiderSushi/sonic-pi-via-pulseaudio/blob/main/sonic-pi-via-pulseaudio

I find that this helps deliver an easy and quick user experience, and most importantly to me it also allows using sonic-pi via bluetooth headphones without additional configuration.
For me this seems like a useful setup that allows trying out sonic-pi and making first steps with it on many linux distributions without knowledge about sound servers.

I can see how this setup is far from optimal, that it can produce audio issues and how users who know what they're doing will prefer running JACK directly for minimum latencies.

All in all this concept is just an idea, feel free do with it whatever seems useful to you.

[rbnpi]

I've been having a p[lay with your script on the latest raspberry pi OS which now uses pulseaudio. When I run it, it sets things up apart from connecting the SuperCollider:out_1 and SuperCollider:out_2 ports to JACK to PulseAudio :front-left and :front-right ports. There is an error in the script window saying ERROR SuperCollider:out_1 not a valid port. I can get it going by starting QjackCtl and manually putting in the connection in the connect window.
Any idea how to get the script working properly?

[SebiderSushi]

Did you try increasing the sleep 5 duration to more than those 5 seconds?

I used my script on a PC but since a Pi would likely be slower i suspect that it probably takes longer until supercollider is up so the script would try wiring up things a little too early.

Generally speaking you can adjust the sleep call to the duration it takes from launching sonic-pi until you want
to start hearing stuff.

The script could use some additional logic to wait until supercollider is launched but i figured that just waiting was simple enough :D

If the JACK-over-PulseAudio concept was to be implemented as an option within sonic-pi itself, these things could of course be properly timed in a stable way.

[rbnpi]

I'd tried 10 seconds but looks like I needed to go even higher on the Pi (currently Ive set it to 20). Thanks.
It may be worth adding stuff to check when SC is running, as we don't want to lengthen the startup time too much, especially as it may vary with different Pi models.
EDIT also it would be nice to get it working with a blue tooth speaker as well, but I'm not sure if this will work. (it shows a an A2DP sink in pavucontrol.)

[SebiderSushi]

I have added a sleeping loop to the script in my gist in my repo. It should now wait until SuperCollider appears on the JACK server and also checks that sonic-pi is still running before trying to connect the plugs.

The zero-conf bluetooth devices perk only applies if you configured them to work with PulseAudio of course, which has already been the case for me so that was nice.
Once everything is wired up as intended, you should be able to get the sound from sonic-pi onto any device that shows up in PulseAudio.

I'd be curious if applying this method on a Raspberry Pi or any other device with a little less computing power causes issues, especially since PulseAudio does resample loopback devices.

[rbnpi]

I have incorporated your script into Sonic Pi with a modified scsynthexternal.rb file. Details are at
https://gist.github.com/rbnpi/8812203f5c9a995620bed9ce3a3c6a20

I am not explicitly unloading the modules on exit, but it seems to work anyway. On a Pi 400 and on a Pi4 performace seems OK, but I think that keen users would still launch QjackCtl and set up jack directly for better performance. However for average/beginners use it looks OK. I would be interested in your comments if you have a Pi to try it on. It can even working with my bluetooth speaker which is a plus, also fine with HDMI or external usb card.

[HeZike]

I have incorporated your script into Sonic Pi with a modified scsynthexternal.rb file. Details are at
https://gist.github.com/rbnpi/8812203f5c9a995620bed9ce3a3c6a20

I am not explicitly unloading the modules on exit, but it seems to work anyway. On a Pi 400 and on a Pi4 performace seems OK, but I think that keen users would still launch QjackCtl and set up jack directly for better performance. However for average/beginners use it looks OK. I would be interested in your comments if you have a Pi to try it on. It can even working with my bluetooth speaker which is a plus, also fine with HDMI or external usb card.

Thank you very much!!! I have been searching for solution of this problem the whole day, and now it works! I'm using Sonic Pi 3.2.2 on Raspberry Pi 4

[MusheAbdulHakim]

@SebiderSushi I have run your script and no sounds are playing even though the application has been able to start

[SebiderSushi]

It still works on my end (Manjaro Linux, PulseAudio 14.0, jack 0.125.0 & sonic-pi 3.2.2)
@MusheAbdulHakim Launch pavucontrol and check that under the Input Devices tab there is an entry for JACK to PulseAudio and that under the Playback tab there is an entry for the Loopback from JACK to PulseAudio. Make sure that the drop-down Show at the bottom of the pavucontrol window is set to All * if the entries don't show up. Also make sure that the volumes are turned up.
After that open qjackctl, open the Graph window and make sure that the JACK to PulseAudio node is wired up to the same pins of the SuperCollider node that connect to the system playback node.

Tell me whatever did not look as expected.

Edit: I added this guide to the README