Frames Frame Input Latency?

I have the following patch setup in a couple of rows of my modular synth at the moment.

The Dinky’s Taiko module is triggered by a square wave LFO from the Peaks on the left.
The same trigger pulse is sent in parallel (via the Links module) to the VC Sequencer.
The VC Sequencer modulates the Frame CV input on the Frames module.
The 4 outputs of the Frames modulate 4 parameters of the Dinky’s Taiko.

The idea is that using this method, I should be able to sequence an 8-step drum pattern from the percussion module by setting the knobs of the VC Sequencer to different values. This will have the effect of simultaneously modulating 4 parameters of the DT, based on frames stored in the Frames module.

So far, so good.

In practice, though, it doesn’t work very well. What I get is very inconsistent results. Sometimes a given VC Sequencer step produces one set of CV values (and thus one sound on the DT module), and sometimes a different set of values.

My suspicion is that there is variable latency on the Frame input of Frames, so that, at the point the Dinky’s Taiko is triggered, sometimes the CVs from the Frames module have changed, based on the CV from the VC Sequencer, and sometimes they haven’t. Does this sound likely?

This is kind of frustrating as this exact setup is one of the reasons I decided to buy a Frames.

a|x

Do you have slew set on the Frames? If so, try turning it off.

However, why do you need the RYO VC Sequencer in this patch? Just use the step sequencer mode in Frames directly?

Does the Dinky Taiko reads its CV inputs only once when it receives a trigger, or continuously?

@pichenettes good question. For a percussion module, it makes more sense to read (or at least apply last-read values) only at trigger time. I have a feeling that’s what it does.

@BennelongBicyclist I’ll have a look into Slew. I hadn’t consciously turned it on, but it may be on.
I was using the VC Seq because I wanted to use keyframes on Frames to create 3 distinct drum sounds, and I could do this with 3 frames. It would be fiddly to repeat the same values for all 4 parameters repeatedly, in order to use Frames sequence mode. I’ll give that a go, though, as it would allow me to make sequences longer than 8 steps.

a|x

From the Dinky’s Taiko manual;

All input and control values are ‘snapshotted’ when a trigger is received - once a drum hit is playing the controls have no effect on its sound (The accent and choke trigger input however do have an effect).

That makes sense.
I guess the problem I’m experiencing is probably the same for any digital module that reads CV at a finite rate. Sometimes it’s going to see a changed value at trigger time, and sometimes not.

It’s a bit frustrating, as I’d always assumed trigger pulses in Euroland are supposed to sync modules with rock-solid timing. I guess that doesn’t apply to MCU-driven devices, however.

Anyone else come across this or a similar issue.

Assuming there’s no slew on the Frames frame value, is there any way I can get the setup described in my original post to work reliably?

a|x

toneburst> Assuming there’s no slew on the Frames frame value…

Don’t assume, check!

toneburst> …is there any way I can get the setup described in my original post to work reliably?

Remove the VC sequencer from the patch and use Frames in step sequencer mode instead, as I suggested above. If it still doesn’t work as expected, at least you know that the RYO VC Sequencer isn’t the cause, and you can put it back into the patch. If it does then work, then you have a likely suspect.

It’s not a matter of MCU-driven or not. Even an analog circuit with a trigger input (say a VC-switch, an analog step sequencer, a S&H) will slew to its target value in a finite amount of time. Similarly, I’ve sequencers or CV/Gate interfaces in which the CV lags behind the trigger (and this prompted me to add the trigger delay option in Braids).

I’d say get a drum synthesis module that doesn’t have a built-in S&H on the CV inputs :slight_smile: Or bug the guys at ALM to release a firmware update in which the S&H can be disabled. It’s also fun to modulate synthesis parameters during the progression of a drum sound!

As a temporary fix, what about multing the peaks square wave back into the other channel of peaks, and using the trigger delay mode to delay it very slightly, so the Dinky always triggers after the new CVs have been read. Send the undelayed trigger to the VC Sequencer > Frames> Dinky, with the delayed trigger into the Dinky trigger.

@DMR: huzzah, great idea! (Damn it, why didn’t I think of that…)

@DMR aha! I was just looking up trigger delay modules on Modulargrid, as it happens. I had the same thought, but had forgotten Peaks did trigger delay, too. Such a useful little module!

a|x

Or actually, just the VC Sequencer clock could be delayed. This would make syncing other modules with the percussion module easier. Downside would be that the values picked up by the Dinky’s Taiko would be offset by one step relative to the current step indicator of the VCS, since the DT would be picking up the CV values from the previous step at trigger time.

a|x