Ghost gate/gltich using MIDI configuration

[Tamanoir]

Hello everyone,

I'm back with a problem I'm having trouble to understand

When notes are played, there are glitches as if the gate send is jammed with ghost gates.

Setup:
Equipment reduced to a minimum for the test:
Nerseq -> Expander -> 3 uDCO (MIDI) - GATE-> ADSR -> VCA ->
- CV -> VCA

Observations:
The problem does not occur when I use the classic CV configuration.
In this example, I have a track configured for MIDI. I'm using three uDCO oscillators configured to receive MIDI only.
Each note is sent to MIDI channel 1, 2, or 3, depending on the available oscillator. (Note that the photo uses channels 2, 3, and 4, but I also had the problem on channels 1, 2, and 3.)
All three MIDI sends are affected by this issue; they all seem to have slightly different audio glitches.
In the video, I play them one by one, isolating each oscillator so that you can hear them clearly.
The glitches are not affected by the MIDI channel selection.

https://www.youtube.com/shorts/4EbMPvfl3T4



Video Commentary:

• The first note played has this jolt that happens quite quickly. It's like a response to the initial gate. In the video at XX seconds, you can see that the response accelerates when I accelerate.
  
• the second note played is often doubled, as if there were phantom gates.
  
•  the third note has a glitch similar to the first.
  

Finally, the notes played at the same time, but it's less clear...
Sometimes the glitch also occurs when releasing the gate, but this isn't always the case.

Suspect cleared:
The oscillators are not the cause. The problem also occurs when I swap them out. I tested them on a different power supply, and I even sent some back to Nicolas from Soundforce, initially thinking that was the problem...

The keyboard and the cable are not the problem. In any case, the issue is the same when I manually enter notes in the Nerdseq
The problem doesn't come from the ADSR envelopes; several have been tested.
I also ran a test by connecting only a MIDI-compatible jack from the expander to test each oscillator one by one, bypassing the box that multiplies the MIDI signals; the problem still persists.
Currently on firmware 2.02A, but I had the same problem before.

Potential suspects:
The problem therefore lies either in:
- The Nerdseq MIDI settings or possibly the MIDI expander
Do you have any ideas on what could be impacting note stability and creating these ghost notes?
I have a feeling there's something wrong with my MIDI setup, but I'm having trouble understanding what I'm missing.

Here are the settings for this example:



Thanks for the advices ,sorry for my google trad English 

[XORadmin]

Hmm, if you only got a sequence on the first column with a note on (like C-3) and a couple of steps later a note off (like late enough that you would normally hear the ghost glitch). Does the ghost note appear then as well?

I would in the first place point to the things you connected to the TRS Midi port causing the trouble. And not because they are faulty but maybe a configuration thing.
You don't loop back to the TRS-Input either?

[Tamanoir]

Hmm, if you only got a sequence on the first column with a note on (like C-3) and a couple of steps later a note off (like late enough that you would normally hear the ghost glitch). Does the ghost note appear then as well?

Yes, the ghost note also appears.

I would in the first place point to the things you connected to the TRS Midi port causing the trouble. And not because they are faulty but maybe a configuration thing.
You don't loop back to the TRS-Input either? 

That's what I thought too. In normal use, here's the configuration.
My keystep keyboard is plugged into the USB host port.

A MIDI cable (jack->din) is plugged into the TRS-A OUT jack.It goes to the MIDI multiplicator. Nothing else.
When I test by plugging a jack (with enough rings to transmit MIDI signals) directly from the expander's TRS-A OUT jack to the MIDI jack of one of my oscillators, the problem also occurs.

In this test, obviously, I can no longer transmit information to multiple oscillators simultaneously, but the glitches are still present when I try them one by one. But I'm sure the problem occurs before even entering the box that multiplies the MIDI signal.

[XORadmin]

Hmm, if you only got a sequence on the first column with a note on (like C-3) and a couple of steps later a note off (like late enough that you would normally hear the ghost glitch). Does the ghost note appear then as well?

Yes, the ghost note also appears.

I would in the first place point to the things you connected to the TRS Midi port causing the trouble. And not because they are faulty but maybe a configuration thing.
You don't loop back to the TRS-Input either? 

That's what I thought too. In normal use, here's the configuration.
My keystep keyboard is plugged into the USB host port.

A MIDI cable (jack->din) is plugged into the TRS-A OUT jack.It goes to the MIDI multiplicator. Nothing else.
When I test by plugging a jack (with enough rings to transmit MIDI signals) directly from the expander's TRS-A OUT jack to the MIDI jack of one of my oscillators, the problem also occurs.

In this test, obviously, I can no longer transmit information to multiple oscillators simultaneously, but the glitches are still present when I try them one by one. But I'm sure the problem occurs before even entering the box that multiplies the MIDI signal.

Keystep input seems not to be the issue then.

And if you connect the keystep directly to the multiplicator or the uDCO without the NerdSEQ?

[Tamanoir]

Hello,
Here's an update on my problem.
After a few more tests and still at a standstill, I dismantled all the modules from the rack in case one might be causing a problem.
I further reduced the number of modules for testing.

Two configurations were tested:
1) Keystep 37 connected via MIDI to a uDCO with a DIN 5 to mini jack MIDI cable connected to the uDCO's MIDI port, then directly OUT to the mixer.

2) The Nerdseq sending a note or sequence through the Nerdseq's MIDI expander. (MIDI OUT mini jack to MIDI mini jack on the uDCO, then direct OUT on the mixing console)

The problem persisted after removing all the other modules in both setup (1 and 2).
In these tests I noticed that the problem does not come directly from the gate jack which is not even connected. We hear what I suppose to be the Note ON / Note OFF signal in the note pitch which emits the clicks that we hear on the first post

I then moved the setup to another home, with a different electrical circuit. Without success.
I brought it back to the studio. 

During my last test session, and to complicate the problem , only one of the three uDCOs exhibited the glitches.
I isolated it and will try again with the other two uDCOs, but I've already had the problem with all three oscillators simultaneously in the past.

I always encounter the same two types of problems.

• The most common is the clicks that seem to be related to MIDI ON/MIDI OFF triggering. (first post)
  

• And the second, less frequent glitch, where the note becomes unstable and saturated until it becomes nothing more than noise. I have the impression that it triggers more quickly when I play many notes in a row. Here's a video of the second type of glitch that I hadn't posted.
  

https://youtube.com/shorts/k86vohOIsL8?feature=share

The good news is that I can eliminate Nerdseq and the midi expender from the list of suspects.
The not so good news is that identifying the problem is complicated; I've spent about ten hours testing and at least as much research.

I think the problem may come from:

• The rack itself, but that seemed strange to me. I have two Arturia 6U racks, and the problem occurs on both. 
  
• I'm researching the DIN5 MIDI cable to mini jack. Some wiring can be problematic. When all five cables are soldered to the DIN connector, some users recommend soldering only the bare minimum for MIDI.
  

• Or my oscillators, which, for some reason, are incompatible with the rest of my setup.
  

I'll try the following:
I received a Bitbox Micro as a Eurorack sampler. Due to MIDI issues I haven't even tried it yet. 
I'll try using it via MIDI, controlled by keystep or Nerdseq, and see if I have any problems.

I might ask for help on a more general modular synth forum, although I'm always open to advice if you have any . In any case, thank you for your quick response.

[Liquidcolor]

My experience with the Nerd and MIDI has been trouble free. Multiple MIDI tracks and synths going with notes and CC.

When I listened to your first video (on my phone) it didn't sound like an issue with gates. but rather modulation of the frequency or phase of the oscillators.

I would suspect the Arturia power supplies, which are not the quietest. Do you have any other cases to try?

[XORadmin]

It doesn't matter if all 5 pins are soldered. The jack itself uses only 3 pins of these.
Can't say anything about the ghost sounds though. I would think of 'hanging notes'.