Question on Edges, Yarns and MIDI and all that

Hi all, I am quite intrigued by some of the Mutable Instruments eurorack modules, but as I am fairly new to all this I have a few questions: There seem to be more and more digital oscillators available and some indeed sound really good. What I find puzzling is the need to have a Midi/CV interface (DAC), a small cable, then a ADC to play them via Midi. It seems to make a lot more sense to (also) be able to play them directly via MIDI (*).

For example, MI Edges offers an optional MIDI-expander. While the documentation is not too detailed, I understand that it provides the possibility to play notes via midi (polyphonic or multitimbral). But would I also get the gate outs to use as gate/triggers for external envelopes or VCAs (I know that the ADC won’t turn into DACs but digital I/O are sometimes a bit more flexible)?
So would this MIDI expansion allow me to play Edges as as multitimbral MIDI sound source, including trigger or gate out, if needed? Could the V/Oct-ins still be used, either to offset pitch, or even to shape the VCA (then its almost a self contained synth-voice)?
[btw: what does “NES_TRIANGLE_CLK outputs the same frequency as Channel 1, multiplied by 16” mean? So if I play an A4 (440Hz), it will output an A8 (7040Hz)? anyway, different topic …]

Similar: Yarns can also act as a simple multitimbral digital oscillator. Does this include a corresponding gate/trigger out, to use it as a self-contained synth voice, adding just ENV and filter as additional modules? Such a possibility would be great for either a minimal setup, or for someone to begin with not too many modules.

More general: Will Braids also get a MIDI expansion? Does anyone know other eurorack oscillators that can be used straight with MIDI and provide a gate/trigger out? I found this one (never heard of the company before): http://www.modulargrid.net/e/emw-midi-oscillator
How difficult would it be to transform the famous Shruthi into an oscillator module? Not the entire synth (already suggested&dismissed several times here), just the oscillator MIDI-in, audio out, gate-out, plus maybe the existing CV-in to modulate some osc. parameters. All the ENV, LFO, Filter would be replaced by external modules. If a bad idea, why?

Comments are appreciated!

ps/disclaimer: (*) I am fully aware that a dedicted V/Oct is very useful in many cases. But this is not what I am looking for here. I am just asking if it’s not a lot easier to skip the digital-analog-digital conversion in some applications, and to what extend such solutions are available.

> It seems to make a lot more sense to (also) be able to play them directly via MIDI (*).

Yes, sure, but while MIDI and keyboards seem obvious in the non-modular world, they are more of a rarity in the modular world. Most users don’t want or need it.

> But would I also get the gate outs to use as gate/triggers for external envelopes or VCAs (I know that the ADC won’t turn into DACs but digital I/O are sometimes a bit more flexible)?

No. On a modular, you’re never connecting something to digital I/O pins directly (if this happens, this is terrible design). There are always buffers/level shifters/or at least protection resistors and diodes to protect things - making digital inputs and outputs irreversible.

> So would this MIDI expansion allow me to play Edges as as multitimbral MIDI sound source, including trigger or gate out, if needed?

Playing notes, yes, gate outs no!

> Could the V/Oct-ins still be used, either to offset pitch, or even to shape the VCA (then its almost a self contained synth-voice)?

No, because if it were possible, it would make keeping things in tune a mess! When you start playing from MIDI, it takes over the pitch received on the V/Oct input.

> So if I play an A4 (440Hz), it will output an A8 (7040Hz)?

Exactly. That’s for feeding a logic circuit that ultimately generates a true digital NES triangle…

> Similar: Yarns can also act as a simple multitimbral digital oscillator. Does this include a corresponding gate/trigger out, to use it as a self-contained synth voice, adding just ENV and filter as additional modules?

Yes, there is a gate out next to the CV out :slight_smile:

> More general: Will Braids also get a MIDI expansion?

Could be possible with a DIY board + firmware tweak effort (3.3V uart input at the back). But certainly not my priority

> How difficult would it be to transform the famous Shruthi into an oscillator module? Not the entire synth (already suggested&dismissed several times here), just the oscillator MIDI-in, audio out, gate-out, plus maybe the existing CV-in to modulate some osc. parameters. All the ENV, LFO, Filter would be replaced by external modules. If a bad idea, why?

Terrible idea. It would be a super crappy version of Braids.

Oscillators are usually not midi-to-cv converters, I doubt any eurorack oscillator(not mini synth) is capable of transforming your midi input to CV and Gate/Trigger.
The gates on the Edges are inputs, I can’t see how that should reverse itself if you add midi data.
My understanding is that the midi data would allow playing, but absolutely no CV/Gate output, unless the module contains a midi/CV translator. (Apart from main out, which is audio anyhow.)

1. “Similar: Yarns can also act as a simple multitimbral digital oscillator. Does this include a corresponding gate/trigger out, to use it as a self-contained synth voice, adding just ENV and filter as additional modules? Such a possibility would be great for either a minimal setup, or for someone to begin with not too many modules.”

On the front panel each of the 4 possible voices that can be controlled/generated by Yarns has a gate and a CV out.

2. There are modules specifically made to transfer audio to CV (Synthetic Sound Labs V-Gates is one I can think of). But before looking into that, you should read up on the way eurorack synthesis works- I had to do the same myself. The “West Coast” synthesis method differs greatly from the standard expectations. You’ll find out the combination of clocks, gates, ADSRs, ADs, and LPGs to get the results you want.

Also, I think I’m confused by your question: why would a fully operational, self-contained synth voice need to send gates or triggers out? They would just need to send audio out and receive gate/trigger and Pitch. You want the same module that sends gates/trigger/pitch to Edges to send it the same to the other voice you want to trigger (or send it on a delay or send it halved or transposed down, etc .)

@morcego: You may want to try out True Grid as it can really demonstrate how powerful a modular can be without midi.
It is very common to use sources as gates/triggers. A square wave LFO can trigger an envelope instead of just acting as an LFO to control cutoff, pitch, ect. Modulars aren’t just bulky monosynths. :slight_smile:

Also, if you were to use your Shruthi as an oscillator, you can run midi through it to a converter. The only property that you cannot affect externally is pitch and other osc settings like mix and pwm. However, The Shruthi has built in envelopes and LFOs to do that. Using external gear for filtering and amplifying just frees up the modulators for the oscillators. On a side note, the Shruthi makes a great drone box too.

A single oscillator that has MIDI control would not be terribly useful in my opinion. In that scenario, yes a gate would have to be provided because you are basically having the oscillator act as a MIDI-CV interface and the gate would have to exist so that you can trigger the envs. Such an interface would be rather simplistic (as well as bulking up the module size). And then you’d have to configure each one.

The Yarns type module, where you have a central MIDI control, is a better approach. It allows more design room for splits, poly, and fun features. And you only need to set your MIDI channel once. :slight_smile:

Having said that, MIDI does makes sense for complete semi-modular blocks; it is in some ways its surprising that I can’t think of a Euro voice block with a MIDI port for convenience. (I guess it isn’t a priority because almost everything in Euro is CV. Hence: The Dark Energy had MIDI, but the A-111-5 Euro module did not.)

@soundwave106: “Having said that, MIDI does makes sense for complete semi-modular blocks; it is in some ways its surprising that I can’t think of a Euro voice block with a MIDI port for convenience.”

What about this (with Eurorack panel option)?

thanks for the comments! I am seeing a bit clearer now (and will definitely try TrueGrid).

@RyanA4: “Also, I think I’m confused by your question: why would a fully operational, self-contained synth voice need to send gates or triggers out?”

Actually, I was thinking something much much simpler: if you want to play a digital oscillator via MIDI, the digital -> V/Oct -> digital conversion is not really necessary. Why not simply plug MIDI straight into the DCO. However, you would still need a gate out to built a full voice, to use envelopes for example.

My question was simply about bypassing a dedicated MIDI-interface, nothing more. But a direct-from-MIDI oscillator might also offer some possibilities, like pseudo-polyphony, where chords share a common ENV and filter. Not straightforward when you use digital -> V/Oct -> digital conversion (you would need like 4 or more individual DACs+ADCs, a full Yarns or similar, possible, but a bit overkill).

@audiohoarder: i agree, it’s certainly “modulars as bulky monosynth playable via MIDI” territory. But why not, I always liked bulky monosynths :wink: (and never claimed this is the first or only reason to look at modulars).

ps. not sure about the “would be a super crappy version of Braids”, but such an oscillator would certainly cannibalize into Braids territory without adding much that cannot already be achieved with Braids, so understandably not a priority for Mutable Instruments. I should also try the CVpal, it also already includes an oscillator, and with gate out :wink:

It would be crappy because you would be menu diving instead of plugging in your CVs and tuning it up.

I think you’ll soon see that the lack of a bunch of MIDI cords plugged into your modular is a good thing =)

> “I think you’ll soon see that the lack of a bunch of MIDI cords plugged into your modular is a good thing =)”

yes, probably … but should I ever get Yarns, there they are again! :wink:

btw: does anyone know that the MIDI-out on Yarns is good for? (just curious)

> btw: does anyone know that the MIDI-out on Yarns is good for?

  • MIDI-thru.
  • Chaining (half the notes in a part handled by Yarns, the rest forwarded to the MIDI OUT).
  • Synchronizing stuff with Yarns’ arpeggiator/sequencer clock.
  • Sending to MIDI the notes generated by Yarns’ arpeggiator/sequencer.

ok, thanks!

@BennelongBicyclist: Ah, good one, for some reason I always forget about the Anushri Euro option.

@Morecego: The problem with poly applications, if you put MIDI ports on individual oscillators, is that each individual oscillator would have no idea what to fire off when it receives a series of poly note messages from a synthesizer. MIDI is simply single messages; the message will say nothing more than something like “note C3 on (or off) in channel one.” Something has to take these messages and make the decisions on allocating the note on / off messages to free slots, whether or not to steal a voice if all slots are full, what rotation order to use, etc. So polyphony is more than having multiple converters, you need dedicated logic code too.

This is what Yarns (and any poly MIDI-CV converter) will do for you. :slight_smile: I suppose with a built in MIDI on an oscillator you could use a MIDIPal or another MIDI processor that can do poly to mono voice allocation to do the same thing. But, then again, that makes this solution also not straightforward.

@soundwave106: it was just an example, here the single DCO would already be polyphonic (DCOs, technically). Voice allocation would happen inside the module, precisely because of the difficulties you describe if using a conventional MIDI-CV interface. What I was thinking was a bit like the Anushri Euro option, only that ENV and filter are provided by external modules … in particular useful for a DCO since it spares the additional digital -> V/Oct -> digital conversion.

It just seemed very odd to me that even with DCOs people prefer to go through the digital -> V/Oct -> digital conversion, rather than straight with the digital signal to the DCO. So it made a lot sense to me that Edges has an optional MIDI expansion that avoids the need for a dedicated MIDI interface and I was wondering why not more digital oscillators provide such a feature (of course, only for those who want to use a MIDI signal in the first place, if not, then no need for neither Yarns nor a MIDI-in). But demand for such an option is obviously very limited … so be it :wink:

I know it was mentioned before, but isn’t this pretty much exactly what Yarns in DCO mode does?

@joshuagoran: yes, I think so. That’s why I asked. Yarns should be good to start with and then maybe add a more sophisticated oscillator later, and keep using the other voices as simple DCOs, until all are used to drive other stuff.

Yes it’s great no matter how many other modules you have, which is why I’m going to regret not getting it now: it’s really one of the best modules there is for both people starting out and for people going forward.

I’m just locked into this Cirklon and it makes no sense to not get the CVIO and BOB. I will be able to program polyphonic stuff with it, but not as gracefully. Plus, it’s function as a simple DCO makes it work as part of- almost any setup. I think about being able to both drive 2 voices and sync another 2 to each and have a master pitch (to then send into quantizers/freq. shifters) with about 8 patch cords all together. Pretty amazing.

It’s so good, it makes me consider selling the Cirklon (which would be a mistake, but the thought is there now…), and just using the Octatrack with my modular.

… hum i wrote a response before but it got lost. not good.

Anyway, i just wanted to wrap-up things: i now build a CVpal (first sdiy soldering ever, … and it works, great kit!).
CVpal allows to output a pulsewave on the gate out. And I find this extremely useful. Together with Peaks and Ripples (don’t have Ripples, but still … another filter/vca works as well) it is already a minimal synth voice. I would love to see something like CVpal with a “real” midi-in, and maybe more waveform options on the cv-out (like a modular miniYarns).

But even with the usb version i am tempted to get another one, and make a small usb case, one cv-pal for synth (either the turbocharged mode, or with clock), the other to trigger drum/percussion. maybe not 100% what a modular should be used for, but still … sounds like fun.
And I still see a case for direct-from-midi DCOs, they make great minimal synths, in particular when there are also cv/gate outs to process the sound further downstream :wink:

Braids and Edges are not DIY products and therefore have to be designed to fit in with the rest of the modular world. This means CV.

A MIDI Braids would be a monosynth and a massive overlap with the Shruthi.

> Braids and Edges are not DIY products …

well, depending whom you ask: http://www.mutable-instruments.net/forum/discussion/3329/diy-eurorack-modules-#Item_265

anyway, this was not at all what i meant … i don’t want to repeat too much, so just briefly: i was intrigued about Yarns to also function as a direct-from-midi DCO. Never saw something like this, and thought it would be very useful. If you want to play or control via MIDI (and sometimes want!) why go through the hassle of DAC -> analog -> ADC for DCOs, which requires calibration and all that (not to mention that modular midi interfaces are not really cheap and have limited precious channels).
So for many applications a simple (or complex) digital waveform that can directly be played via MIDI seems like a good idea – and this is exactly what Yarns does (also no DIY product, except for the most ambitious among us)!

You can indeed use Yarns to built a, or actually four, simple synth-voices. Note that this is not a monosynth. It is just the DCO and a gate signal, the filter, vca, envelope all still has to come. And CVpal does a bit the same, albeit with a more restricted waveform (via its gate out). And it is indeed fun to use! I just build a little synth with 3 modules, CVpal, Peaks and a filter/vca combination. So it’s a DCO, an envelope, a LFO and a filter. Functions very well in the modular world.

Actually EDGES also works as a direct-from-midi DCO, it just lacks the gate outs. And such a direct-from-midi DCO can also have some advantages compared to proper midi-CV, such as pseudo-polyphony that then runs through a common vca and filter … but here i go again (and, yes, i admit that its a bit a niche idea in the modular world, but still …).