#1

How do Monome-based sequencers handle CV and gate timing? I’m looking at usin a Doepfer A-192-2 CV to MIDI interface module. It’s docs specifies that the ‘CV Voltage must be present at the rising edge of the gate signal’.

Good to go, or possible problem?

Thanks

Kria or other Monome module control of midi synth?
#2

curious about this too…

firmware wise white whale updates gates first, then CV, orca updates CV first. but i think regardless the gap is so small in theory it shouldn’t matter, but only testing would confirm. and would be trivial to change the order if that would help, but it might also be the case that a DAC would take longer than a gate output (and there is likely a slew applied to it). additional delay could be introduced but then you get into a weird territory where it makes it work with A-192-2 but introduces a noticeable latency otherwise.

#3

The module came today, so I’ll test this weekend.

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#4

sounds good. if it doesn’t work and you have the time and desire to try i can also send you a customized firmware (either ww or orca) with an additional delay and we can figure out what works (away this weekend but can do it once i’m back next week).

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#5

The gate update is pretty much since it’s digital IO on the microcontroller itself. The CV update needs to transmit new values via SPI to the DAC and then the DAC needs to respond and change the voltage. It’s hard to audibly perceive, but if the CV-to-MIDI converter responds to the gate immediately then it will sample the wrong voltage. We have the same problem with the Metropolis and I’m in the process of attempting to correct it so that CV recorders will work correctly.

Ideally the gate states should not change until the DAC has finished updating its voltage output.

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#6

yeah, this makes sense. i guess the question is to choose a delay that makes it work with any quantizer / s&h and anything else that samples voltage upon a trigger but is still low enough to not make it audible.

the latency introduced by the DAC must be low enough, since there are no audible pitch changes when using in a simple patch (CV out to 1V/Oct, gate out to an envelope to a VCA).

#7

The delay is on the order of 10s to 100s of microseconds, depending on the SPI speed and slew rate of the DAC. Really you just need to measure it on a scope and then delay the changing of the gate appropriately. As long as the gate / trigger change after the pitch it should work with any module which will be sampling it.

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#8

Following up from the testing I’ve done with monome-based sequencers, other eurorack sequencers and the Doepfer A-102-2 CV->MIDI interface.

Tests passed.

No problem that should affect anything other than extremely fast, and by that I mean a flourish of notes that probably couldn’t be distinguished under any circumstances.

Sending MIDI to several AUs I have, i.e.: AAS Chromaphone, AAS Ultra Analog and u-he Diva, the notes and gates I sent were performed as expected. As mentioned above, I did notice in Chromaphone that when I cranked up the tempo of a eurorack sequencer (Verbos Multi Stage in this case) there was noticeable missed notes in the flourishes. But, I’m not sure this would translate into any real world problem.

The A-192-2 is easy to use - I made no modifications to the factory default settings. Plug USB into the module, plug a gate and a CV into he respective inputs on the module, config the AU, etc. on the computer to see the module (on my MBP, the module was identified by the full name of the module, so easy to locate), and it is good to go.

If interested:

This is the first I’ve used my modular with my computer. I’ve tried to keep things all modular. But recently I realized that 1) I have so many great sound generators on the computer that are going unused, and 2) I don’t perform regularly, so the imposed "keep the setup simple’ limitation I imposed on myself is unnecessary.

At this time I only intend to use Chromaphone (great percussion) and some additional AUs that will be used primarily for drones/atmospheric purposes.

Cheers. (I’m not British, but like the sentiment!)

Thanks to all who provided me assistance.

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#9

thanks for the detailed report! this definitely puts the 192-2 onto my wishlist.