Oxe FM Synth

Published by the european magazine Computer Music

“The best Freeware FM synth…” by CreateDigitalMusic

Published by the japanese DTM Magazine
(issues 2007-01, 2008-03 and 2008-09)

Current version: 1.3.5 (2016-04-19)


Oxe FM Synth is an open source VST 2.4 instrument plugin for Windows, Linux and Mac OS X.


  • Multitimbral (16 MIDI channels);
  • 8 operators (6 oscillators, 1 noise generator/limiter, 1 filter), all with envelope;
  • 1 LFO per channel;
  • frequency modulation half-matrix with self-modulation;
  • global reverb and delay;
  • great general performance in low resources systems;
  • a lot of good quality patches included (thanks to Annabelle, Summa and Teksonic);
  • external skin support (download lcd, snow, tx802 and dx7 skins by Layzer, totolitoto’s skin by David Frappaz, fm8like skin by Alan Wasky) and sytruslike from “some random dude”.

Listen below some of the many tracks composed using only the Oxe FM Synth patches from the contest One Synth Challenge edition 81:

Click here to download the latest version

The source code is on GitHub


v1.3.5 (2016-04-19)
– Linux: fixed blank GUI bug;

v1.3.4 (2015-11-17)
– OSX: using accelerated graphics (OpenGL);
– Linux: fixed possible issue on GUI loading;
– all: fixed possible crash when the GUI is shown on DAW project loading;

v1.3.3 (2015-10-20)
– Windows: fixed bug on closing GUI;
– Linux/OSX: fixed bug on loading external skin;
– OSX: fixed bug that prevented some hosts to recognize the plugin;
– all: fixed bug with some skin’s images with an old DIB header;
– new skin “DX7” by Layzer;

v1.3.2 (2015-10-12)
– Windows: version number update only;
– Linux: fixed crash on close GUI;
– OSX: native version released;

v1.3.1 (2015-09-26)
– stability bugfix;
– native Linux version released;

v1.3.0 (2015-09-01)
– new feature: full automation (on channel 1);
– new feature: show values on mouse over;
– new feature: double click to set default value;
– new feature: host undo/redo support;
– all parameter changes are now applied immediately;
– removed the “compare” function (right click);
– the “store” button now is only used as “copy” function;
– fixed the fine tune display value when keyboard tracking is off;
– fixed bug in LFO rate control;

v1.2.2 (2015-08-06)
– 64 bit version available.

v1.2.1 (2015-05-04)
– Added mouse wheel support;
– Implemented a compare function (just click on right mouse button);
– Fixed stop of mouse drag when beyond the window boundaries;
– Fixed bug that blocks the virtual keyboard of some hosts;
– Fixed effects bug;
– Fixed default skin (buttons Store and Program swapped);
– New skins ‘snow’ and ‘tx802’ + 33 new bass presets by Layzer.

v1.2.0 (2015-04-15)
– Fixed aleatory pops on envelop decay;
– Fixed sustain pedal not working;
– Fixed synth stuck after some time;
– Fixed out of tune problem when sample rate other than 44100Hz;
– Fixed incorrect save state;
– fixed program name editing;
– fixed vst host integration bugs;
– Better knobs behaviour;
– MIDI bank select using LSB as index;
– Embedded soundbanks (bank0 by “Nolwenn a.k.a Annabelle”, bank1 by “Summa” and “Teksonic”) [for convenience, existing soundbanks are loaded from the filesystem but not saved back in original file];
– No registry use;
– No installer;
– External skin support.

v1.1.2 (2004-04-01)
– Fixed the problem caused when the filter resonance is zero;
– Added new bandlimited saw and square waveforms;
– Fixed the problem with release time of OPZ;
– Is allowed that the frequency of an operator starts in 0Hz;
– Changed the units of coarse tune knob in LCD;
– Added a new switch, per program, called “High Quality”;
– Added inverted values for Mod Wheel Destination;
– Fixed saved state of channels on GUI;

v1.1.1 (2004-02-16)
– Fixed the problem of total silence with some hosts;
– Improved the VST SDK 2.3 integration (program and bank management, .FXP/.FXB, midiProgramNames);
– Fixed the GUI LCD update when the program is changed via MIDI;
– Added a solution to edit program names in Tracktion (Trackion get all keystrokes from plugin and activate its defaults key-mappings);
– Added a algorithm to reallocate notes when the polyphony was exceeded.

v1.1.0 (2004-02-06)
– Translated some error messages that remains in portuguese;
– Added a bank navigator;
– Added knobs of Reverb and Delay sends per channel (in a moment, this is do via MIDI controllers);
– Added a dialog box to choose the output sound device in EXE version;
– Fixed the problem of knobs that don’t was showed;
– Fixed the send of names of programs to the VST Host;
– Fixed the problem of different sound banks for VST and EXE;
– Fixed the problems to rename the patches in VST Version;
– Fixed some minor bugs;
– When the application is closed the state of channels is saved;
– Fixed the problem of stuck notes.

v1.0.0 (2004-01-02)

25 thoughts on “Oxe FM Synth

    • Marco, once it is open source anyone can provide updates. Nowadays I’m working on another personal project, so I don’t have short term plans to add new features.


  1. Oxe operator feedback is ‘pre’ envelope ( the amplitude envelope doesn’t influence the feedback amount , which it should.
    The feedback should be POST envelope.
    So it’s impoosible to go from saw —> sine with just 1 operator ..and a decaying envelope
    A real shame ,since you can’t get that dx behaviour .


    • also if you use fm8 skin you will notice that every modulation index goes down only to 7, below that it’s zero so you can’t have subtle modulation.


  2. I tested your Keyscanner with a PRO MINI (without velocity) It works pretty perfectly, but one question: What’s the purpose of ‘KEY_SUSTAINED_RESTART’ and the LED (PIN13)


  3. I have added to Cakewalk and can edit etc. but not getting any sound whereas other VSTs supplied with Cakewalk do produce sound. I am sure I must be doing something stupid. Any ideas? Any issues with Cakewalk? Thanks.


  4. Hi I can’t seem to get this to appear in my plugins on ableton live 10 (on mac). It’s there in my VST folder but when I scan for it, it won’t register. Any ideas?



  5. Bonjour,
    Avez-vous une idée de comment l’installer ? Une fois le zip téléchargé et décompressé, je suis perdu…
    Merci d’avance !


  6. Hello. I am visually impaired and I liked the synth fm. I would like the controls to be accessible. Currently I can only work with the parameters available for automation. I use Reaper and the Osara accessibility extension. Thank you for reading.


  7. The Effects settings are not being saved when you save a patch. Nor when you save a project file in your DAW. Tested with two DAWs.


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