Synthino XM Polyphonic MIDI Synthesizer & Groovebox


Minneapolis-based DIY kit makers, Michael Krumpus (nootropic design) and Alex Dyba (GetLoFi) have announced Synthino XM – a new synthesizer that’s being produced via a KickStarter project.

Synthino XM is a 5-note polyphonic synthesizer, with 4-track sequencer.

Here’s a video intro to the project:

Synthino XM is a polyphonic, multitimbral synthesizer with many features:

  • 5-note polyphony
  • 12 waveforms, 4 drum samples
  • 12-bit audio at 25KHz output rate
  • 4 MIDI channels, each with separate waveform and ADSR envelope
  • low pass filter with cutoff frequency and resonance controls
  • 2 independent low frequency oscillators (LFOs): pitch and filter
  • selectable waveform for LFOs
  • 1V p-p audio output voltage with enough current to drive headphones
  • arpeggiator mode, up to 16 notes
  • 4 arpeggiator patterns: up, down, up-down, random
  • 4 built-in arpeggiator chords or use MIDI to specify up to 16 notes
  • arpeggiator pitch transposition control
  • tempo control with MIDI clock input
  • 16-step live performance “groovebox” sequencer
  • pitch fine-tuning adjustment
  • programmable/upgradable over USB

Here are official audio demos:


The Synthino XM is available to project backers starting at US $129.

Related Links:

19 thoughts on “Synthino XM Polyphonic MIDI Synthesizer & Groovebox

    1. Yes, the software is all open source. Developers will be able to modify the functionality, add new samples, etc. Development requires the standard AVR gcc toolchain and a simple utility to upload the file over USB. The project started as an Arduino-based synth, but since the Arduino IDE does not support the more powerful ATxmega microcontroller, the IDE can’t be used for compiling/uploading. But since all the code uses the Arduino API, any Arduino developer will feel right at home. Hope that helps.

  1. too cool, i love these little toy noisemakers. there is something especially fun about making it yourself. i dont know if i would call it an emotional attachment or anything, but turning assorted parts into a useable instrument just makes it a liitle bit more special.

    1. As a technophile myself, I would say that feeling is something very close to emotional attachment. But that’s just me.

    2. Just to be clear, though, it’s not a kit that you assemble. This is a fully assembled device. It also comes with a 9V battery, USB cable, and 1/4″ mono to 1/8″ stereo audio adapter. Plug and play.
      We have considered offering a version in the future that the customer assembles – you guys want that? Can do.

  2. For the price of one Oberheim SEM, I could have several of these Synthinos. Yes I know the Oberheim has more features, but 3 or 4 of these could make a LOT of music. The specs are a little fuzzy. Does this unit have a filter for each of the 5 notes it can play? Or does it share one filter? If it has only one filter, then this is a paraphonic synthesizer not a polyphonic synthesizer. It sounds like there are only 4 ADSRs, which makes me wonder.

    1. There are 4 MIDI channels, each with their own envelope parameter and waveform settings. The settings are applied to any note played on that channel. Up to 5 notes at a time can be played, so they might all be on the same channel (like if I’m playing with my keyboard on channel 1), or the 5 simultaneous notes can be spread across all 4 channels if I’m using a DAW sequencer. In that case each channel has its own distinct sounding instrument (waveform and envelope settings).

      Each played note follows its envelope independent of other notes, so a note’s envelope doesn’t “start over” when another note on that channel is played.

      The filter is global. If I had more CPU cycles, I could apply the filter differently to different channels, but I just can’t make it run fast enough to do that.

  3. is it only 9 volt powered?it would be nice if it has either bus power or a wall adapter – still really cool little device though

  4. Ah, another cute device to suck me in! Looks like a nice companion to my Meeblip Micro, Nebulophone, Patchblocks etc. 🙂

    1. I might be able to add another mode which is a monosynth. All the same functionality as synthesizer mode, but the output rate would be 44100 Hz. If I don’t add this as another mode, never fear because the firmware is updateable and a high quality monosynth would just be an alternate firmware that the user could load. That’s the beauty of being able to update the firmware over USB.

    1. A portamento feature is not too much for the processor. It’s really a matter of how many features can be implemented given the number of buttons/knobs. The UI constraints are always the hard part. I suppose I could add a secondary function to the “button pitch” pot in synthesizer mode that would control the portamento speed. A reading of 0 would mean “off”.
      I may be able to sneak that feature in before release, but it can always be added later, as the firmware of the Synthino is upgradeable over USB. There will be many versions of firmware with different features. The USB update capability really gives me a lot of flexibility.

Leave a Reply