MIDI Sequencer

Hi there,

a while back, I started developing ideas for a monophonic synth. Beeing half way in the build, I realised I have already way more synths than hands to play them.
So I put the synth project aside for a while and started thinking about a sequencer. I really dig the elektron-way of sequencing (elektron analog four, rytm, octatrack, etc.) so I used their layout and interface as a base for my project. The sequencer basically is a mixture between an octatrack and an analog four taylored to produce streams of MIDI on four (or more) ports. OSC and CV/Gate is planned. The former might get hard to realize, but I’ll see what I can do.
Today I finally managed to get the basic functions into a working condition. I can now enter notes and parameter locks, configure which ports and channels are used for the notes and to which MIDI CC number the parameters should be sent to. Oh and the sequence actually plays! Wohoooo!
I was so happy building up the first sequences, I couldn’t resist to make a short video.


The project is based on an STM32F429 Discovery-board with 8MB of external RAM for all the sequencing information. Software is written in C/C++. Software and hardware will be fully open source once the project is finished (or at least close).

Just to be clear: I won’t sell parts of it / kits or whatever. And it might take a while before this is in an acceptable condition. Please don’t expect this to be finished before in a year (or even more…). I’m just too excited about it and can’t keep this for myself :smiley:

Impressive. You say you’re not planning to sell kits, but will you Open Source it?

Yes definitely!

Very impressive !

Nice! Well done :slight_smile:

Uhh nice!

Thanks for the kind comments. I’m super happy that it works out. That processor is a beast. I’m still a bit scared about the MIDI stuff. I have four independent midi outs for a total of 16 tracks. Each track has 40 MIDI CC or NRPN parameters. If I run heavy automation on all the tracks, I expect the MIDI messages to get delayed. I need to implement a way to avoid buffer overflows… MIDI is a terrible protocol for such things.

Yea, there are some fundamental problems to be solved. Maybe I have to add more midi ports or remove tracks or restrict the density of MIDI messages somehow else (e.g. by limiting the number of parameters, etc…)

You should find somebody who is willing to make some kits for this! This looks really amazing!

Hmm, I’m a little afraid about the legal aspect. Not sure if Elektron patented their concepts (the surely have…). Gotta ask them.
On the other hand: This is far from being usable. So much stuff to be done. Let’s talk about kits when its finished!

You might want to change the placement of the controls and modify the graphics in the UI to make it less Electron-like while still retaining the core concepts.

Cool. Very!

Second what t2k said. You might end up making something that is even better… who knows!

I have no experience with Elektron gear, but I guess that keeping stuff where muscle memory finds them is a huge plus for Elektron fans who want to sequence other gear.

I would modify graphics, but the placement helps those accustomed to Elektron gear.

a lot of people conplain about Elektron screens, go bigger ! :smiley:
Anyway, really nice work, try to implement more than 4x16 step, something like 8x16 would Be awesome !

A different screen colour might help with the “looks like Elektron” problem.

@Lamouette: It is 8x16 steps already.

Regarding the Elektron-or-not debate: I have changed some things about the way notes are entered. Don’t want to go into the details here, because it might (and most likely will) change anyway. So: I’m already implementing my own ideas.
But many of the controls are kept similar to elektron gear because I don’t right now see a better way to do it. IMHO their interface and workflow is amazing, that’s why I used their ideas in the first place. For some features I had planned a different way to do it but then I came back to the Elektron-way because I realized it was soooo much better.

But I have a distinctive feature: The fader works for Midi parameters (I don’t get why that’s still impossible on the OT) :slight_smile:

I look forward to watching your video. Sounds cool.

Anyways, let me hear what you would like in a MIDI sequencer!

Here’s what I have in mind:

  • clock in and outputs for modular/volca, etc. (clocks can have swing applied!)

  • CV/Gate extension (why not?)

  • OSC output (if I find enough free I/O). It would be so cool to remote-control a behringer x32 - shame I don’t have one…

Any additions?

PS: this is only brainstorming. Most of the above features are far, far away and might not even get implemented at all.

Just be aware of the licensing restrictions on the STM Discovery and Nucleo boards - strictly speaking, you are not supposed to use them in any published design or product for sale, not even open-source ones. However there are Olimex STM32 boards which don’t have any licensing or usage restrictions - you might want to investigate those. For some discussion of this, see the thread here

That said, STM are unlikely to complain, but it would be very annoying to put a lot of work into a hardware design, only to receive a cease-and-desist letter from the STM lawyers.

@TheSlowGroth: check Rolf Degens De:Generator, he’s using a pretty big screen for the UI, might work for you as well!