New DIY FM Synthesizer – preenFM

Reader Xavier Hosxe sends word about a new DIY synth project, preenFM.

preenFM is an open source and open hardware project that lets you build a hardware FM synth module.


  • 9 different FM algorithms with up to 6 operators
    • Each operator includes a pair of oscillator and ADSR envelope
    • Oscillator : 7 waveforms (4 sin variation + noise + square + sawtooth), linked to keyb freq or fix, fine tune
  • Up to 4 voice polyphony with 3 operators FM algorithm, up to 3 voice polyphony with 4 operators FM algorithm and up to 2 with 6 operators FM algorithm.
  • Glide available when voice set to 1
  • 3 standard LFOs (4 waveforms (saw, ramp, square, random), frequency in Hz, ramp up to 4 seconds, reset on new note).
  • 1 Env type LFO
  • 8 rows modulation matrix – 12 different sources and 24 destinations
  • 4 banks of 128 user presets
  • System exclusive to exchange patches and banks with a computer
  • Midi control : 44 control input/output control changes linked to parameters
  • Nrpn : input/ouput of all paremeters
  • Midi channel selectable : Midi for other channges can be forwarded to plug several PreenFM in serial
  • Large readable 4×20 LCD
  • Friendly surface controle : You always clearly see on the screen what you’re currently editing
  • Sampling rate : 32768 Hz (Makes integer division faster). Pseudo 11 bits.
  • 1024 Hz for LFO and modulation matrix
  • 6th order butterworth analog filter to convert the 1 bit output into a nice waveform
  • Transparent case that allows you to see every day your nice work

preenFM is going to be made available in limited quanities in mid-December. Hosxe says that there will be a batch of 20 kits, priced at 130 euros + shipping for the full kit.

See the preenFM site for details.

7 thoughts on “New DIY FM Synthesizer – preenFM

  1. So, what have we learned from this video?

    How NOT to make a synthesizer product video:
    1. Show us the silent box for five minutes while the designer mumbles on about how f—–g great it is;
    2. Give a cursory demonstration with really poor sound;
    3. Be vague about price and availability;
    4. Fill the video with feeble jokes and gimmicks.

    How to make a GREAT synthesizer video:
    1. Show us the box, features, knobs, connectors etc. briefly from all angles;
    2. Give us a full and thorough demonstration of the capabilities, cool sounds and software features;
    3. Let the product speak for itself;
    4. Make sure the video features one or more provocatively-oiled sexie laydeez, as we all know that sex sells.

    Pity about (4); however, in eight minutes (which felt like three), Xavier did a superb job of selling me this device. Thanks Xavier; I now know that I want one. 9.5 out of 10.

  2. Great to see a hardware synth at a good price. Hardware beats software any day.
    Well done, FM synths are great. The yamahe dx 100 is the classic!!
    Well done

  3. That’s cool, 2 oscillators per operator is pretty slick. Like the rockit I think I have to pass even though I really want both. I have purchased too many synths in the last year (never thought I would say that). It’s a testament to the amazing amount of cool affordable diy synths there are nowadays, (I finished my shruthi1, haven’t even got to my sammichFM or my meeblip, like I said, too many synths)

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