An ARM-Based DSP Modelling Synth


The great analog synths of Moog, Oberheim, Sequential Circuits, and more modern version from Doepfer are renouned for their sound, the sheer majesty of a rack full of knobs and plugs, and of course the price. Analog synths are simply expensive to build, and given that aficionados even scoff at digitally controlled oscillators, require a lot of engineering to build. [Jan]’s DSP-G1 isn’t like those analog synths – it uses microcontrollers and DSP to generate its bleeps and boops. It is, however, extremely cheap and sounds close enough to the real thing that it could easily find a home between a few euroracks and CV keyboards.

plugThe heart of the DSP-G1 is a micro from NXP modeling an analog synthesizer with 15 digitally controlled oscillators with Sine, Triangle, Pulse and Saw outputs, a low frequency oscillator, two envelope filters, and a low pass filter, or about the same accouterments you would find in a MiniMoog or other vintage synth from the 70s. Since this is basically a synth on an NXP LPC-810, [Jan] has packaged it in something akin to a MIDI to 3.5mm cable adapter: Plug a MIDI keyboard into one end, an amp into the other, and you have a synth smaller than the MIDI Vampire, an already impossibly small music creation tool.

[Jan] has a few more versions of his little DSP device with varying amounts of knobs available on his indiegogo campaign. The DSP-Gplug is the star of the show, though, provided you already have a MIDI keyboard with a few knobs for the required CC messages. Videos and sound demos below.

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42 thoughts on “An ARM-Based DSP Modelling Synth

  1. Very cool and not price prohibitive. The smallness is amazing to me even in this day and age of tiny things. Nice work! I will be tossing my money in the hat (after I clear it with the wife). It would make gigging a breeze – you just pocket the dongle and walk up to the bar after the show. Nice! One of the better thought out and executed projects I have seen in a while. Kudos.

    1. No, you cant.
      The software is the dsp-G1, the soul of it.
      The software is what I’m selling.

      If I put that out it could be run on any platform and I would have nothing to sell?

    1. I can assure you its not a scam.

      If you run it as fixed funding and don’t reach the goal no one is getting anything except their money back.

      This way at least some of the synthesizers gets delivered.

      1. The purpose of these sites is to raise enough money to start production. If you can make them without raising capital to start production, why not use a web store? If you had done this, I would have bought one. With flexible funding on indegogo, you can take the money and not deliver a product. So I agree with fake-name, flexible-funding = Scam.

        1. Most of the projects on Indiegogo / kickstarter seem to be VERY far along. Not much development needs to be done. Some have “high” getting-into-production costs and use the crowdfunding site to “pre-sell” enough stuff to warrant the tooling costs for a production run. But you could do that on your own website as well. Offer the product with a later delivery date and let people preorder!

          Sometimes the company doing the kickstarter already has the ability to do small production runs. And they can handle a smaller volume than what they are asking for in the campaign. Maybe they are fine with selling the “leftovers” at a leasurely pace later on.

          But in both cases, it is a marketing tool. You get exposure. You get noticed. And that’s worth a lot.

        2. I have spent the entire winter programming, building and putting this together.t
          Three words from you “It’s a scam” crashes all of that work in seconds.

          Why do you do this?

          It’s not an unbelievable router with a screen that routers don’t need.
          It’s just a simple synthesizer?

          I bet every time you get a parking ticket is a scam?

          Just let me do my project and no one will get scammed.

    1. And complexity?

      It does the same as the JP-8000, wraps the waveform.
      No analog sybthesizer can do that because it’s impossible.

      in the real world that is PWM on any waveform, not just the squarewave.

  2. when people talk about modelling synth usualy they mean physical modelling synths. You can have an example of modeling synth looking at for some theory and to user manuals to read about some examples. I would not call this one a modelling synth, maybe a functional modeling synth but the correct technique to describe this is additive sinthesys .

      1. Wow.. Bad attitude :( Hack a day could bring you massive exposure to large number of potential customers, don’t drive them away dude. The question about modelling synthesis seems valid.

  3. I don’t like when people start screaming scam.
    This is my baby and I have spent 6 months making it real.

    I love playing it and will depart from each unit with great love.

    Hope that you are one of those that are fortunate to receive one.

    1. Unfortunately, the internet has given a voice to hundreds of people who, realising that they’ll never achieve anything themselves, have instantly set about trying to punish anyone who looks as though they might.

      Good luck to you! It’s not my cup of tea, but it does look nifty :)

      1. janost,

        You’re probably about to get a great education in the science of product development and marketing. People are skeptical because most products die at the 98% complete stage.
        It’s why VCs don’t like to give start-up founders “living expenses”…

        This is usually because the guy putting “his baby” together runs out of steam with the first almost working prototype. Sometimes it’s because a hacker doesn’t realize that (most of the time) getting a project built is only about 30% of the work required to convert it into an income stream. It’s very similar to a programmer saying his code project is 98% complete.

        Good Luck! Big Fan of the Juno series btw. Black Leather Monster for the win!

  4. I spent a long time making it sound like the juno-106.
    Every part of it is modeled after the juno.

    Does it sound like a juno?
    Yes, sort of. Along the way it got it’s own soul and sound.

    But it’s still the dsp-G1.
    Sounds analog.

  5. NXP provided me with the platform.

    Comparing the ATmega with an ARM LPC is like comparing a Skoda with a Ferrari.
    It doesn’t compare.

    And the LPC is a great musical platform.

  6. wow – I really love the idea of the plug form factor! I believe that a tiny product like this is feasible and absolutely possible. The magic is in the algorithms and implementations.

    However, the currently shown “plug” version looks like it might be a stock photo of an existing regular plug or photoshoped? I can understand people crying “scam!” because because the HaD post makes it look like this is the final product already. I think this plug is rather in the stage of “concept art” (but it is not clearly labled as such!).

    I’d guess he’d get more credibility if he showed the current status (PCB demo) actually playing. The posts only show plastic boxes with knobs – and the video shows someone playing a keyboard…

    1. The plug in the picture is actually a hacked connector converter.

      The delivered synth plug will look a bit different to show that it’s a synth and not just a connector plug.

      It must also host the MIDI activity LED and the plug in the picture cant do that.

  7. I don’t get how you set the synth parameters (like attack, decay, envelope, etc…) when the plug does not have any controls itself. You have fixed preprogrammed sounds on various MIDI channels? Or you have to program it using computer before each use to get desired sound? And finaly… What is this?:
    It does not look as plug synth. it is some device used to program it? or it is completely different synth? How it’s related to plug synth?

  8. For all of you grumpy bi*ches, I have sold my first 100 chips to Adafruit and going for the next 100.
    Either your not musical or as I think, you hate other peoples success?

    It is a success :)

    And the dsp-Halo is up next. 2Gb DIY Gigasampler.

    1. >For all of you grumpy bi*ches, I have sold my first 100 chips to Adafruit and going for the next 100.
      Either your not musical or as I think, you hate other peoples success?

      Tragic attitude, reflected in your toxic postings here, muff wiggler and elsewhere, where people complain about terrible service from you, delivers that don’t turn up, lack of contact for months on end.

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