Just a quick update … using the latest prynth image and after installing pisound AND with a bit of tweaking (for instance copying quarks into a node_module context) I have a really solid 3.9 auto run env AND the supercolliderjs editor.
Slick … I’m doing granular arpeggiator nonsense to the nines and, frankly, it’s more fun with the pi than with the laptop …
The jack settings need to be tweaked a bit more … but the the whole stack is basically started and run via node. WTF. a javascript server. but it reduces the boot cron (pi user crontab) to starting node.
grab this image (or get the code from github if you want to go the extra mile) and edit the wpa_config while the image is mounted … and PM me with questions 
I’ll try to do a write up soon but it’s really the nicest/easiest way I’ve found to run supercolider with the pisound.
AND it sounds GREAT!