Figuring out remote GUI for Zynaddsubfx on Zynthian

Hi, just finished my Zynthian platform: Sharing is caring - A custom Zynthian box :heart_eyes: :heart:

Now taking the next step and figuring out how to control Zynthian remotely. One of my questions is how to get full control over the ZynAddSubFX layer. I use
ssh -X -C root@zynthian , inspired by: Accessing Zynthian from your computer - ZynthianWiki

However in the process list I see that ZynAddSubFX is started as layer (-U option) without a GUI, so I need to start a new instance, which defeats the purpose of accessing the existing layer remotely. Btw, that new layer perfectly forwards via SSH to my X11 session on my laptop.

Who has accomplised a remote ssh -X11 connection of an existing Synth layer?

Hi @Jan. I’m glad you have built a Zynthian and joined this enthusiastic band of degenerates. Say goodbye to hours of your life as you get engulfed in the good, the bad and the ugly of this little treasure trove.

The instructions on the wiki are out of date. (Note to self - tell someone to fix that!)

The best way to access the GUI of the engines is to enable VNC:

  • Connect via web browser to webconf
  • Navigate to INTERFACE->UI Options
  • Assert Enable VNC Server option and press Save
  • Reload webconf and navigate to INTERFACE->UI-Engines
  • Enter the Zynthian password (default: raspberry)

You should now see a desktop and the GUI for any engine launched (after enabling VNC) will display here. There are some exceptions but most of the interesting ones are there.

I have updated the wiki with this info.


Interesting, as newbie already hit the max message limit for the first day :-). Happy that the moderator can’t say that I’m a passive member…

Anyway tried that and worked. My vnc is accessible via: Software → VNC Viewer… Saw also that my RPI hit 100% CPU with ZynAddSubFX layer so I’m gonna add passive cooling.

And indeed a treasure trove it is. Really amazed by what has been included in the Zynthian image. Many thanks for answering my question Riban.

ps: sorry for not responding. The hands of this Dutchy were tightly knit.

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The new ZynADDSubFX’s native GUI is really CPU-hungry and slow. Nothing we can do, except stepping back to use the old “classic” GUI. Regarding the cooling, unless you see the “red thermometer” icon in the status area, improving cooling is not going to improve performance.

Also, i strongly recommend to disable VNC when it’s not being used.


Thank you Jofemodo. Just tried that. Indeed switching of VNC results in dramatically lowing CPU. In my case, only after connecting VNC with the browser increases CPU. VNC running without using it keeps it down. Disconnecting browser after using VNC still keeps it high.

I have just installed a internal passive heatsink which lowers the temp from hitting 83 degrees within 1 min to 69 degrees after 10 min, while continously playing three ZynAddSubFX channels and cpu 90%. If this is not enough I plan to add a a small external heatsink. For now this problem solved.