MicroDexed Touch Is An Open Source FM Groovebox

MicroDexed Touch is a fork of MicroDexed, which is a port of Dexed for Teensy 3.6/4.1 with a lot more functionality including multiple sound engines (2 x 16 voice DX7, 2x VA Monosynths, Layered Multi Samples, MDA ePiano, 8 voice Mutable Instruments Braids Oscillator), Euclidian arpeggiator, basic audio effects and a 8 track pattern song (tracker like) sequencer.

MicroDexed Touch is an advanced DIY project, based on a Teensy 4.1, PCM5102 Audio Board, 320×240 ILI9341 SPI Display with XPT2046 Touchscreen and a serial Flash Chip.

MicroDexed started as a Teensy based, 6-operator-FM-synthesizer. MicroDexed Touch offers a lot of new features/improvements:

  • “Large” Graphical Interface, view and edit multiple Parameters in one Screen
  • Use external MIDI gear over USB or MIDI Mini Jack (DIN MIDI with adaptor) from 2 x 16 MIDI Channels in the Sequencer
  • Map MIDI CC to external MIDI Devices to control Input/Parameters
  • Loading, playing and editing multi-sampled instruments or layered instruments in a “live” mode or played by the sequencer. Auto detection sample zones but also can be edited manually
  • 2 new “Virtual Analog” Synth Instances – Monosynths with one OSC, PWM, Filter and Noise. A lot of useful new sound possibilities. This module is called “MicroSynth”
  • Much improved Sequencer with 8 Tracks, 16 Step Patterns, 16 Step Pattern Chains, up to 16384 Song Steps, Arpeggiator with 1/8 – 1/64 Steps, Arp Patterns, Pitched Drum- and Instrument Sample Support
  • The sequencer can also play chords stacked up to 7 notes, using only a single track
  • Mixer View with all Channels
  • Multiband Master Compressor with 4 bands
  • Sample Management from SD-CARD and SPI FLASH, samples can be loaded/modified from SD-CARD to FLASH during runtime.
  • Touch Mute Matrix for live / realtime performance
  • Tracker View (Editor) – work in progress
  • Track Print/Recording – work in progress
  • Mutable Instruments Braids Oscillator – with up to 8 voice polyphony, added envelopes and filters, with everything of the core features, except the wavetables

See the project Github page for details.

via TheEvilDrSmith

32 thoughts on “MicroDexed Touch Is An Open Source FM Groovebox

    1. So do I, but I’m getting a little too old to take those kinds of projects on any longer (I can’t see for shi*!). However, if somebody was to package this thing as an assembled unit, I’d buy one in a heartbeat for about $250-$450. Considering that I recently paid $170 for a Volca FM 2 (that I really don’t think is worth near that much now that I have it), I think that price range is very reasonable considering what you would be getting. On the other hand, I think I’ll review the project and, if I think I can oversee its construction, ask one of my more engineering-inclined students if they would help me build it for a couple hundred bucks.

        1. Nothing really “wrong”, its just that Korg totally missed the boat, I think, especially at the price point. First, it is a total bitch to get patches into it because there still is no SysEex capability. Next, unlike Dexed running on a vanilla Win 7 PC, I can hear subtle, but noticeable, differences in the sounds the Volca makes compared to my TX7 or to Dexed (and I’m not talking about the noise floor or distortion inherent in the TX7). I just received a $100 (with Shipping to the US) USB cable I purchased from Retrokits in Saturday’s mail. Supposedly, that gets around the SysEx problem, but it does add over 50% to the cost of the Volca. After I ordered the cable, I asked myself why I did it to salvage a synth I probably will just give away. I had a lot of hope for the Volca FM when I ordered it, but to say I am disappointed would be a hell of an understatement. If you are thinking about buying one, get a cheap used Windows laptop and Dexed and you’ll be a lot happier for the $270 you might need to spend.

          1. What sysex capability? You need a midi usb interface with sysex capability, not the other way around. Any audio interface with midi would do.

            1. I’m not sure what you are saying, but unless you use something that specifically addresses the issue (like the Retrokits special $100 MIDI cable), you can’t load patches into the Volca over MIDI as SysEx. Yes, you can still send the SysEx as an audio “bleep” stream through the audio input, but that is retarded in today’s age (might just as well go back to saving patches on audio cassettes). That it can’t do that most obvious thing (given that they market it as being compatible with DX7 patches), makes purchasing it, for other than as a toy, kind of senseless.

          2. Just to clarify. Since I ordered the Retrokits cable so long ago (over 2 weeks) I forgot what it was, exactly. I just opened the package and it is a MIDI DIN to MIDI DIN cable (not USB). Apparently, it has an electronic circuit inside one of the connector shrouds that “fools” the Volca and allows the patch SysEx to go through the MIDI port and be interpreted correctly by the Volca.
            Note: That’s what it is supposed to do but I haven’t tried it yet.
            Note 2: There is no USB connector on the Volca FM 2, and that’s probably why it needs either physical batteries or an optional 9v power supply.

              1. No, it isn’t a scam. I’ve been dealing with Retrokitts for a couple of years now, and they are quite legit. For example, they offer one of the best MIDI routing systems currently available and it is only about the size of a pack of king sized cigarettes. As to the “special MIDI cable”, it is, indeed, special because it actually contains a microprocessor and it can be programmed. That’s how it gets around the Volca MIDI SysEx problem.

                1. It works for everybody with a normal midi interface just fine, but our pro guru expert mister John Rossi needs a special $100 cable xD

                  1. Name one person it works for? But, you can’t, because it just doesn’t work, period! Do you even have one, or have you personally loaded a patch onto a Volca FM, through the MIDI port, without using another device between the Volca and whatever you are sending the SysEx from? Obviously not, otherwise you wouldn’t suggest that it is possible. Also, is it really necessary to insult me instead of determining whether or not I might be correct? Just keep on embarrassing yourself!

                    1. Again, please cite even just a little bit of evidence that supports your statement “It works with every audio interface with midi connectors”. The reason you can’t is because it doesn’t, and no matter how hard your brain tries to make it so, it won’t. Granted, I may be old, but I fail to see what age has to do with correctness of an assertion. I know that I’m correct about this because even Korg has discussed the issue. What I am surprised about is that nobody else who reads this list besides me, apparently, owns a Volca FM 2 (or Volca FM 1, who doesn’t use a program in Max or a Retrokits cable to communicate with it through MIDI [for the transmission of patches via SysEx, that is]).

                  2. He’s talking about the RK-002. It’s a cable with an integrated MCU. you can program it. Not as scam at all, it’s great. Retrokid does make really awesome stuff and they’re far from being scammers.
                    That said, it’s not $100, more like $50. So he might have got ripped off by some online shop I’ll give you that.
                    This is the thing he’s talking about:

                    1. It was 53 Euros when I purchased it, and shipping and handling to the US added about another $25, I think, so I stand corrected. I did purchase it directly from Retrokits, however. Still, my point remains the same, give or take about $25.

                    2. Could somebody please let me know the rule that governs what URLs are permitted to be included in a post here and what URLs aren’t? The whole issue of the inability to send patches by SysEx to a Volca would be so much easier to conclude if I could just enter a definitive URL and be done with this pointless argument once and for all.

                  3. OK, I’d like to apologize to everyone here for my obvious overblown defense of my proposition that it is impossible to load a Volca FM preset using MIDI. I WAS WRONG! It can be done, using an external editor running on a DAW, through, as Dad has contended, a standard MIDI interface. Here, I concede that maybe my age is a factor in that I forgot why it was that I felt required to purchase the Retrokits MIDI cable. After looking over a number of reviews of the Volca I realized that my short term memory maybe isn’t what it used to be. Apparently, the reason I purchased the Retrokits cable was to correct the real SysEx shortcoming of the Volca. What the Volca can’t do is to SAVE presets using SysEx via MIDI, opting to use the “SYNCH OUT” as an antiquated audio interface to accomplish the task. So, I was wrong on a number of counts, and again, I apologize. From now on, I will check things before I make assertions that I wouldn’t be able, in the long run, to defend.

          3. Yeah…not sure what kind of trouble you are having but I get patches loaded into my version 1 Volca FM and it’s super easy. Can even program the thing from a Max for Live patch. I actually pass midi through my Monologue to the Volca.

            1. I didn’t say that you can’t load patches into the Volca, it’s just that you have to load them through the audio input which is, really, late-70s technology. I’ve not used Max nor do I know what it can do (obviously, the Retrokits cable gets around things somehow). However, in a stock Volca FM (either one) you can’t load patches by SysEx through the MIDI port. That you need to purchase either a $100 cable or a $700 Mac-based sequencer (if that actually works, and I haven’t seen anybody else say that it does) to do it is my point. The $170 synth becomes either a $270 or $870 synth depending on how you attempt to remedy the problem.

      1. yeah, todays SMT is way too small for me to work on in bulk. equipment mods (and repairs) though, are definitely worth strapping the bug eyed goggles on, and skipping my caffeine for the day to settle my hands. lol

        get those kids cracking! :0)

        for something like FM Though, I’m more inclined to develop something of my own on Prologue for.

        1. For 6-OP FM you really can’t do too much better than Dexed (assuming the port to the SBC environment is 100%). I have an old TX7 that I keep around because it doesn’t eat up a lot of physical space, and except for the much lower noise floor, Dexed sounds are indistinguishable from those it makes using the same patches. So far, I really can’t say the same for the Volca.

      1. “R slur”? As far as I’m aware, my only violation here concerned my comments regarding the physical appearance of a female narrator which was deemed “name calling”. Seriously, I have no clue as to what “slur” may start with the letter “R”.

        1. Did you google “R-slur”? It’s the first result, if you are “seriously” serious you shouldn’t need to ask for help for something that’s the first google result.

          1. No, I didn’t Google it until you suggested it. Then when I found out what you are referring to, I realized that you obviously have no understanding of what the word actually means in English, when it isn’t being used in a derogatory context describing a person or a person’s behavior (i.e., used correctly in context of the adjectival form of the verb) . Just to set your politically correct mind at rest, this is the definition of the verb I was using and to which you are objecting “to delay or hold back in terms of progress, development, or accomplishment”. I’m sure that the engineer at Korg who decided to implement it that way had an IQ well above 100. That still doesn’t make it a design that keeps up with the current state of SysEx communication between MIDI devices. Also, if you think about it, if I (because I was sensitive to the feelings of the audio port on the Volca) said, “It is a design that reflects a lack of intellectual development”, wouldn’t that be more of a suggestion of some disability attributable of the engineer that implemented it, than the inadequacy of the design itself? Sometimes, it really is a banana in your pocket, just as sometimes using the word that correctly conveys the meaning you are trying to get across makes it the correct word to use.

              1. I’m sorry if you aren’t a fluent English speaker, or somehow have trouble reading a simple definition. The usage and context of my use of the “forbidden” word, in itself, justifies its usage. Nowhere in that statement I made was there any allusion to anybody’s intellectual development or intelligence. This totally a non-sequitur. Words have meanings and no amount of politically correct bullsh*t will ever change that. If that weren’t the case, you would also have to object to the sentence “In order to correct the synchrony of the spark plugs firing, Steve had to retard the timing”.

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