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Discuss MIDI for ER-301 here


Hey Brian. I’d be pretty interested in getting MIDI into the ER301 somehow as could imagine this significantly reducing the use of the CV ins.

Am playing around with the idea of using the ER301 with a Linnstrument which uses as many as 8 channels of MIDI each using Pitch, velocity, after touch, gate and mod wheel.

You mention it could almost be done as a DIY project. How hard would it be to expose the MIDI stream as “ins”?

User Replaceable CPU - THE DEFINITE THREAD - Which one? When? How? Etc
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Hi Ben! I’m not sure how to answer your question since “hard” will depend on the individual. Can you be more specific with your questions please?


I think MIDI IO is an excellent candidate for the currently-unused serial interface. But it seems to me that the gate inputs have sufficient specs to support MIDI input. Obviously this discussion deserves its own topic, but since this lil thread popped up here…



  • There is a UART exposed on the back (from the red CPU board) which is perfect for MIDI expansion but I’m not a big fan of MIDI. I never use MIDI. So probably it would be better if I commissioned someone else to do that. It would be a really simple project. Perfect for DIY too.
  • The USB hardware exposed on the back is device USB only. I am planning to develop USB drivers that will make plugin development easier (live console, command line, mass storage device, etc.). So I’m looking at it as the developer’s port.


I think a few people would definitely be interested in a Midi expansion for sure!


Working with polyphonic samples might be easier to play over midi than CV / Gate too.


Come on, coding a fairly complete MIDI stack takes like 30 minutes. Think of it like eating your broccoli. MIDI file I/O, on the other hand … :skull_crossbones:


Looks like we have a volunteer! :smiling_imp:


Could be fun. Will the SDK provide enough low-level access to enable such an endeavor?


Maybe not right away but eventually yes!


Excellent. I am looking forward to it.


What I think would be awesome would be something like the following:

  1. MIDI DIN connected to serial port on back via a simple expander module
  2. A unit that exposes the MIDI channel data in the ER301 so you could use anywhere. The unit would have ability to select channel, CC# or other events.

Combined this would enable you to add a MIDI unit to say the 1v/oct on an oscillator unit, select channel x, and pitch.

Make sense?

Reason I would love this is am planning on trying to use the Linnstrument as a polyphonic controller for the ER301. With current IO on the ER301, think I can get to 4 channels (it uses 5 fields per channel, so 20 inputs required), but the Linnstrument actually uses as many as 15 (1 control, 7 each side), which is way more IO than we have.

Brian - on the DIY side, I am very comfortable with a soldering iron, but that’s as far as I’ve gone so far.

I2C communication with Monome Teletype

Why complicate it, just use the USB port for the MIDI?

I’ve been trying to ditch the DIN sockets for ages and I am very close, adding a DIN port to the 301 seems like a step backwards. Being able to plug any class compliant USB device into a standard USB port seems both contemporary and convenient!

Otherwise I am back to needing a USB to MIDI converter! Which will be converted back to USB again - argh!


I’d love to see an example of your work, which products have you developed that have a midi stack in that you wrote in 30 minutes? That’s mind bogglingly impressive, you must code like lightning!!!


:see_no_evil: :hear_no_evil: :speak_no_evil:


While I appreciate your comments re. midi - the insults are definitely not welcome, wholly inappropriate and not how we roll here - kindly reign it back in!! :frowning:




oo! This would be great for poly patches, as currently I have to use 12 CV ports for 4 voice pitch/gate/velocity with a QMI (which is a big module). Having this as a single midi port tapping onto the back serial and ellimating the cable spaghetti… yeah!!!


I’m trying to think this through and I’m not sure adding Midi via USB is really going to improve the MIDI situation completely. I too am using MPE controllers. Have you thought about processing overhead and extra workload from having the 301 handle MIDI and it’s routing? Excuse my 301 ignorance, but are their CV outs enough to make this actually useful even?

I personally would like to see the cpu harnessed for something else. I think there are MANY modules that are specifically made for handling MIDI and do a great job at it. Polyend Poly is one that is specifically made for MPE, for example, and using it like this means I can use four rows for the 301, and the remaining four rows can be routed elsewhere in the system. Aesthetically I think this is just cleaner as well.

I don’t know, maybe I’m missing something.



Personally I think if it can be accomplished in a way that it’s an option (and to @2disbetter’s point, consumes no CPU if it it is not in the chain) a MIDI option would be pretty great!

I actually bought a better MIDI to CV module in anticipation of my 301 arriving - wanted to be able to take advantage of the polyphony options. But there may be some patches where being able to free up a lot of the CV ins for other modulation would be nice.

Guess it would really come down to the dance between CPU and free CV ins. To Neil’s point, four voices is a lot of patch cables for just the basics, let alone if you want aftertouch, mod wheel, etc. Wonder what that would translate to in terms of 301 CPU though…