MIDI Out: Inconsistent response to triggers?

[trickyflemming]

I was attempting to use Cherry Audio's MIDI Out with Adroit's MIDI Drum Kit and various Playertron sequencers that output single-sample triggers. I'm running into an issue where the response from the MIDI Out is extremely sparse (usually silence for large periods of time).

As a workaround, I've added a Cherry Audio Trig-To-Gate between the Playertron outputs and the Adroit mapper to expand the triggers into 5 ms gates.

Is this a bug to report to Adroit or Cherry? From what I can tell, the Adroit module is responding to the single-sample triggers and lighting up with activity, so I'm leaning that the MIDI Out is scanning its inputs at a lower sampling rate or something.

[UrbanCyborg]

I've not heard of this, but by all means, refer it to CA support. If nothing else, they might be able to tell you what's going on.

Reid

[ColinP]

Hi,

The MIDI Drum Kit module should handle single sample length triggers OK. That the "LEDs" are lighting indicates that the tiggers are being received.

One possibility is that you're using velocity as well and there's some propagation delay in the patch. The velocity signal needs to be present on the rising edge of the trigger. If it's late by even a single sample you might end up with zero velocity note on MIDI messages (which are interpreted as note off messages).

Perhaps you could post a screen shot of the patch you are using? Or attach a .voltagepreset file.

If you're not using velocity then more generally I've sometimes seen odd behaviour with single sample length triggers in other situations but have so far not been able to figure out why they work most of the time but not always. Also CA's MIDI Out module has given me odd behavioir but I've generally put that down to poorly written drivers on my low budget MIDI interface. There are some old posts on the forum about MIDI issues that don't seem to have been fully resolved.

So there's a range of possibilities here. It would be good to pin this down.

[trickyflemming]

Certainly! I've attached a photo of the patch. I didn't start working with velocity yet on the patch as it was a bit frustrating even getting it to send messages in the first place.

Yes, I'm definitely leaning toward it being the CA MIDI Out and not the Adroit module due to the fact that the redraw activity is showing up on the rendering callback.

Screen Shot 2022-12-20 at 9.44.49 PM.png (2.33 MiB) Viewed 2457 times

[ColinP]

Thanks that eliminates the possibility of propagation delay problems.

I just did a little test sending single sample length triggers to MIDI Drum Kit and then sent the MIDI to CA's Poly Octave Oscillator with its REL (release) control turned up so one can hear brief triggers and it works fine.

I then replaced the MIDI Drum Kit with CA's CV to MIDI module and that works too.

So it looks like the problem is probably either the MIDI Out module or whatever is downstream from it. I noticed you are sending the MIDI to your DAW so there are several unknowns about what's going on there. It might be worth eliminating any issues with very short triggers in whatever sound source you are using in the DAW. Things like drum plugins should handle single sample length triggers just fine but many synths abort their attack phase as soon as the gate drops. So it might be something as simple as that.

If not then my suggestion is to contact CA support with the issue and see if they can duplicate the problem and offer advice.

If you don't have any luck on that front then get back to me and I'll look at adding an option to the MIDI Drum Kit module to lengthen the gap between MIDI events so that you can hopefully avoid the tiresome workaround using the Trig to Gate modules.

Anyway please keep in touch and hopefully we can resolve this.

[SpaceDog]

I've used the Adroit MIDI Drum Kit module, driven by various trigger sequencers,including the Misfit Drum Trigger Sequencer, but not the Playertron one. This was fed through the MIDI Out module and then routed (within Reaper) to a Klevgrand plugin. Whilst it may not solve your problem, here are a few things that I did when getting this to work, which it does perfectly, and in time. You never know, something may help.

You may not need a Trig to Gate into the Adroit module, this depends on what your eventual sound source does with note off information (e.g. mutes the sound).
If you don't need velocity, don't connect it; however, then Adjust does set the fixed velocity level, so turn it right up and back off to taste/need.
Make sure that the MIDI Out module has your DAW selected (obvious, but easily missed).
Check that the MIDI channel out of the MIDI Out module matches the MIDI channel of your sound source.
Ensure that you are routing the MIDI within your DAW from the VM channel to your sound source channel. I use Reaper and it's a dead simple connection. You can check what's energing from VM using a MIDI Monitor plugin, and the same for what's arriving at the sound source.

Apologies if you've done all of that. The thing that caught me out was the Adjust knobs, I had to do the other things until I figured it all out. I was impressed with how well it all sync'ed and then I started playing with more interesting trigger generators and my drums got even more interesting.

[honki-bobo]

Are you using the VST2 or VST3 version of VM? The VST3 standard seems to be a bit quirky when it comes to sending MIDI to your DAW, so a lot of problems may be solved by simply using VST2. There have been some reports about strange behaviour concerning MIDI in the forum, see viewtopic.php?t=1330 or viewtopic.php?f=8&t=869

[ColinP]

Slightly off topic but as SpaceDog raised the ADJUST knobs I looked up my old code and here's some detail...

If nothing is connected to a VEL IN socket then the default base velocity is 95. If a cable is connected then it's the voltage multiplied by 25.

Then the ADJUST knob does a linear 0% to 200% scaling of this base value. At 12 o'clock the scale is 100% (one to one).

Then the result is limited to between 0 to 127. If the result is zero then no MIDI messages are generated.

The idea is that you can produce static velocities across the full range including muting or tweak CV control for different effects and to compensate for MIDI keyboard or pad velocities which might not be very well distributed. When driving a simple sound source the velocity will just affect volume rather than timbre in which case the knobs provide an easy way to perform a submix.

[trickyflemming]

Are you using the VST2 or VST3 version of VM? The VST3 standard seems to be a bit quirky when it comes to sending MIDI to your DAW, so a lot of problems may be solved by simply using VST2. There have been some reports about strange behaviour concerning MIDI in the forum, see viewtopic.php?t=1330 or viewtopic.php?f=8&t=869

I actually tried both! Yes, as a plugin developer, don't get me started on VST3 MIDI... Anyway, yes, I had a similar problem with VCV 2.2 last week when the VST3 was released, but that was fixed pretty quickly. As a result of that, I immediately tried the VST2 of VM out of hope.