New OB-Xf plugin

Software
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Status on this:

So current path to updated version:

Regards,

Bernard

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…or migrate zynthian to Trixie???

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I am curious how much of Zynthian works or falls apart with that newer Debian version, not for the short term but to have an idea of what’s coming.

Update: this could be an interesting experiment on a throw away SD card running latest Zynthian.

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44

The latest OB-Xf code base seems to include support for this. This doesn’t automatically trickle down to Zynthian yet, but it’s good to know it’s coming OR allows to check it out on other platforms in the nightly releases.

Update: clarification of the OB-Xd support, taken from the README

Patches and banks created by OB-Xd are compatible with OB-Xf, using the “Import OB-Xd Bank…” option in the patch browser, or by simply drag-and-dropping OB-Xd FXP/FXB files onto OB-Xf’s interface.
This functionality was introduced in v1.1 update.

Fidelity of conversion is retained in all cases except one. This is due to the fact that OB-Xd has an offset of 12 semitones when all coarse tuning controls are set to 0 semitones - so middle C produces ~464 Hz instead of the expected ~232 Hz. OB-Xf has fixed this reference pitch, and compensates for the discrepancy by increasing the Transpose parameter by 12 semitones. If Transpose parameter was already at maximum, both oscillators are pitched up by 12 semitones. If either of the oscillator pitch controls don’t allow for an increase of 12 semitones, the imported patch will sound one octave lower than in OB-Xd.

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Update: now that

This is something I can do next week when I’m back from holiday.

17 August Update: test results OK

Test steps:

  • Fresh Vangelis beta (Trixie) plus latest updates.
  • Zynthian v5 kit with Raspberry Pi 5
  1. Delete existing OB-Xf directory /zynthian/zynthian-plugins/lv2/OB-Xf.lv2 to work around installation error.
  2. Go to webconf > Software > Engines
  3. Click Scan for Engines and confirm to scan, in order to remove OB-Xf from the list of installed engines.
  4. Click Install plugin and upload the ob-xf-Linux-ubuntu24.04-arm64-2026-08-14-c373dcb.zip file

Test: this succesfully installs the plugin, and it can be played. However, the list of presets still corresponds to the previously installed version, showing 312 presets that have no effect.

  1. Reboot via webconf
  2. Click Scan for Presets and confirm to scan.
  3. Reboot via webconf
    Now the plugin can be run with just the Init preset, and tweaked.

Note: while confusing, this ubuntu zip seems to be the only one with the right lv2 cpu architecture that Zynthian requires.

Open topics:

  • should this ubuntu arm64 build be used?
  • presets are available in the nightly build package ob-xf-assets-2026-08-14-c373dcb.zip, unclear how to install in one step.
  • and of course this is a nightly build but promising once a new release is available. Next milestone is version 1.1.
5 Likes
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Hi all, any suggestions on the open topics above? This is where I don’t know how to proceed.

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I have no idea, but would like to use this plugin as well.

Did you test the GUI? On a previous version, if I created a patch in the gui and saved it, it crashed my zynthian..

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@krullebolle and all,

I tested again today with the latest nightly.
This is the nightly for the upcoming 1.1 release, status here: Issues · surge-synthesizer/OB-Xf

Install steps:

  • Latest Vangelis beta/release candidate updated today.
  • Zynthian v5 kit with Raspberry Pi 5
  1. Delete existing OB-Xf directory /zynthian/zynthian-plugins/lv2/OB-Xf.lv2 to work around installation error. You can use SSH (or e.g. FileZilla) to do this.
  2. Go to webconf > Software > Engines
  3. Click Scan for Engines and confirm to scan. This removes the legacy OB-Xf version from the list of installed engines.
  4. Click Install plugin and upload the ob-xf-Linux-ubuntu24.04-arm64-2026-08-14-c373dcb.zip file (or the newer version available here: Releases · surge-synthesizer/OB-Xf)

Observations:

The many categorized patches can be selected in the GUI :fire: and they are applied.

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Open topics:

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It is probably GitHub CI options that offer Ubuntu as the host OS. For my LV2 plugins I use:

runs-on: ubuntu-24.04-arm
container:
image: debian:trixie

but then chose my own naming convention that does not name an OS but instead refers to the hardware platform (aarm64).

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Thanks @riban, that makes sense.

@krullebolle, saving and loading a preset now works from the GUI without a crash:

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And this is the default layout, not sure if the previous Zyncoder mappings can be used as is or need refining.

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And one more thing…

to enable the new MPE support, take the following additional steps after installing a recent nightly OB-Xf:

  1. In the GUI, press the red MENU button (or click right on the background)
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  2. Choose Themes > Default Vector.

This loads the vector based GUI which contains the new MPE support. In my testing, this is remembered across reboots.

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Use the Gear icon next to MPE to toggle the MPE specific settings:

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Note: to learn about these kind of details, you can join the Surge team’s Discord via Surge Synth Team | Join the Surge Synth Team

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Hi OB-Xf lovers!

I’ve updated the included version in Vangelis. I also created a script for generating the LV2 presets from the native presets. Perhaps you have to restart the zynthian or push “scan for new presets” from the presets option menu.

Finally, i enabled the MPE support for this engine, so it’s not needed the native GUI to do it. Simply select “ALL MIDI channels” for the engine.

Enjoy!

5 Likes