Quadrax Feature Request

[Lokua]

I was just asking about this yesterday on muffs and came here to join for this very reason!

So hello! I’m new here but not new to Intellijel modules, which I love . First module I bought was Intellijel and many more since. ANYWAY.

For reference here is the post asking about what quad envelope generators can do this:
https://www.muffwiggler.com/forum/viewtopic.php?p=3347386#p3346856

I’ve actually had Quadrax off the table (for now at least, who knows how my needs will change down the line) for this reason but out of the other options if Quadrax could do this I think it wouldn’t even be a debate for me. I have a Quadra and that is by far my favorite EG, but that’s got its hands full already

I have very specific use case:
I need to use my envelopes simultaneously for triggers and amplitude on an ER-301 (sample players). If decay time is too long and the envelope does not reset to 0 or indeed low enough to rise up and hit a gate/trigger threshold, I miss beats. Might seem silly or too much of an edge case but doing it this way saves me 4 entire gate inputs on the ER-301 and the ER-301 inputs are pretty scarce resource in my rack despite being 20 of them . O_C gives me this but I really miss the hands on control of my envelopes.

And yes! It will cause clicks! But it doesn’t really pop, I guess? If you have zero attack it doesn’t matter if you’re interrupting the previous env or starting from silence, there will be a click. It’s the pop we don’t want, right?

And that has me thinking - to be specific, just resetting to 0 is great, but can it be done without the click / pop? Or more specifically without more click than you’d get from a zero attack in any case? Perhaps with a fade? I understand perfectly that we can’t time travel, however I’d be more than willing to deal with a known amount of ms delay. I guess it comes down to what’s the minimum amount of time and what curve could be used to ensure no “pop”? How do drum machines and samplers with mono retrigger behavior deal with this?

(Minor edits for clarity)

[0x16161d]

Haha, all this time I thought that Quadrax only didn’t retrigger while mid-attack, but I guess it can’t really retrigger at all?

Your comment inspired me to dig further into my Quadrax and try retriggering it while it’s still mid-decay. Yeah, Quadrax indeed doesn’t even retrigger when it’s mid-decay, which I’ve actually not seen on any other envelope generator (besides Quadrax, I have owned 10 different Eurorack-format envelope generators, 4 of them analog implementations and 6 of them digital). I’m surprised I never noticed this before but I guess I’ve always instinctually molded its attack and decay times to fit whatever gate sequence I’m feeding it, without stopping to think about why I’m doing that.

If the reason Quadrax can’t be retriggered while it’s mid-decay is a concern about clicks or pops, I entreat you to trust us to handle that issue ourselves with the timing of our gate signals and how we set our envelope segments’ durations. Or, as I suggested, you could give us the option of having Quadrax retrigger the envelope from whatever voltage level it is currently – e.g., if it’s still decaying and at 2.5V when the second trigger is received, it will commence its new attack segment from a baseline level of 2.5V.

[Lokua]

if it’s still decaying and at 2.5V when the second trigger is received, it will commence its new attack segment from a baseline level of 2.5V.

Surprised that’s not how it works already - in other words, just like Quadra. In either AD or ASR mode, if receiving a trigger or gate during the decay phase, Quadra will retrigger the attack phase at whatever amplitude it was at during the decay phase. This does not result in pops or clicks or anything because there is no discontinuity.

If you feed it fast enough triggers, with attack at 0 and decay maxed out, you should receive a constant, flat 8v. So if you’re ever in a pinch for an 8v DC offset

So these are kind of two different features. “reset to 0” seems it should not care about whatever segment. Just restart at 0v no matter what. “reset at last amplitude” is really just a way to say “reset during decay”, as “picking up where we left off” during attack, well, that just means the attack will continue to rise towards the next stage as if no trigger happened at all, doesn’t it?

[0x16161d]

So these are kind of two different features. “reset to 0” seems it should not care about whatever segment. Just restart at 0v no matter what. “reset at last amplitude” is really just a way to say “reset during decay”, as “picking up where we left off” during attack, well, that just means the attack will continue to rise towards the next stage as if no trigger happened at all, doesn’t it?

Yeah, this sounds right to me, and I suppose my feature request could be reformulated as a single setting with two options. But the “reset at last amplitude” should actually reset while mid-decay, which Quadrax doesn’t appear to do now.

The way this works on another digital quad function generator (Zadar) that I have, if you have the “analog” (= “reset at last amplitude”) reset option enabled on a channel, it ignores triggers that are received before the “attack” segment has completed, but then once the attack segment has completed, a new trigger will restart the envelope (where the initial level for the attack is not 0V but where the envelope was at when retriggered). If you have the “digital” (= “reset from 0V”) reset option enabled on a channel, it resets from all triggers received (both during attack and during subsequent segments) from an initial level of 0V.

Here’s how that looks (first 7 seconds are the “analog” behavior, remainder of the clip is the “digital” behavior): https://vimeo.com/458390147 . The dark line that tracks horizontally across the visualized envelope shows the progression of the fired envelope and when it’s being reset.

[Lokua]

I decided last night to recommence my quasi annual reread of the famous and excellent Sound on Sound: Synth Secrets by Gordon Reid series. This passage made me chuckle (emphasis mine):

Hang on… what’s all this about resetting to zero? Check out Figure 14 below. This shows the contour of a series of ‘reset to zero’ trapezoid transients. Some synths reset in this way, and it can lead to a very disjointed sound indeed. Because of their slower Attacks and Releases, this is particularly noticeable on some string ensembles where the single envelope generator resets every time it is initialised. Some early polysynths do this, too. It’s horrible, and sounds like the instrument is swallowing its tongue. Glump!

https://www.soundonsound.com/techniques/envelopes-gates-triggers

So good folks at Intellijel, if you do decide to implement a reset to zero option, will you please consider naming it Glump Mode ?

[Minatorymodular]

This behavior might explain some of my difficulties with Quadrax. Especially if it really doesn’t retrigger until the decay is over (I’ll have to go back and check). If you have differently spaced triggers, you have to set the decay to the shortest decay length? That’s strange.

Thinking about it, I’m not sure if I’d prefer reset to zero or retrigger from current level. I think soft synths all retrigger from zero. But retrigger from current level seems more dynamic and interesting.

I think I’d prefer to have both available on different channels (I.E. A kick with consistent pitch envelope by dymanic amp envelope, or vice versa). Maybe the behaviors could be divided between AR and ASR respectively.

[kamil]

I’m not sure where people are getting the idea that the envelope does not retrigger during the decay stage, as it certainly does. Here’s a scope shot from two triggers in quick succession:

The behaviour is the “analog style” where the envelope resumes from whatever level it was when the new trigger occurred.

If there is a retrigger during the attack stage this can make it seem like it didn’t retrigger, because it just continues from wherever it was before which makes it seem like a continuous attack.

[0x16161d]

My apologies for helping to promote this misconception. I must be getting fooled by how it sounds when triggers are fired in quick succession and there’s long decay, and should confirm what’s going on with an oscilloscope.

[0x16161d]

haha, good idea.

I also just want to reiterate that despite how ‘unnatural’ resetting from zero might sound when the envelope is used to modulate amplitude, there are many other use cases in modular synthesis for ramping envelopes where this would be a desirable feature

[kamil]

No problem. Just gave me a bit of anxiety since in some earlier protos the reset was not handled correctly but I was sure it was fixed for the production version…

I agree that the reset to 0 would be useful in some cases, I’ll think about how that could be implemented in a future firmware revision. I think I mentioned in another thread that we’ll have a more elaborate system for “behind the panel” settings coming soon so maybe it will be a part of that.

[0x16161d]

It does indeed retrigger while still decaying. Sorry again for the fake news!

[Minatorymodular]

I did an about-take when you said it didn’t retrigger during decay. Glad that’s cleared up.

I’d think reset to zero wouldn’t cause pops in modulating parameters that aren’t amplitude.

Either way, it’s nice to hear there’s plans for ongoing refinement on an already impressive module. It’s my main modulation source and any changes drastically increase what I can do. The LFV was fantastic addition, as I have no random source otherwise.

[kamil]

I’d think reset to zero wouldn’t cause pops in modulating parameters that aren’t amplitude.

You’d be surprised, even on something like filter cutoff or FM depth you can get audible transients when there are discontinuities in the modulation. Of course, those are not always undesirable and it can be a stylistic choice to have them as part of the sound.

[ohexoh]

I second being able to retrigger the attack phase for the exact same reason mentioned above (scanning recorded Planar wiggling)

[Dadodetres]

Hello!
I wonder if there is, or could be a firmware were the trigger behavior is “full re-triggering” ?
If that would cause pops and clicks, maybe have a “Slew” (maybe with amount? or maybe automatic that is previously scaled to work in conjunction with attack/decay time for “optimum performance”).

thanks !

[0x16161d]

Dear Intellijeans,

I have a feature request for Quadrax that I believe would greatly expand the musical flexibility of its AD envelopes. I would be overjoyed if it were possible.

The request is for an alternative AD functionality that can be selected in System Mode. This option would create so-called “ADSD” envelopes, such as the kind that are offered on the Minimoog, Mannequins’s Just Friends, Xaoc’s Zadar, After Later Audio’s Tilt, and any slew limiter-based function generator (Maths, Function, etc.; this is achieved by sending the same gate into both the trigger input and the ‘slew input’, but attenuating the multed gate before it is patched into the slew input). These envelopes are different from ADSR in that you cannot choose decay and release stage times that differ from each other; the pseudo-release stage’s time is governed by the decay stage’s time.

Here’s an example of how this could work. Let’s say Quadrax is configured via System Mode to output 10V maximum, and the ADSD alt mode is chosen via System Mode as well. If the Trig jack receives a gate whose maximum height is 4V, this channel would produce an envelope that (1) rises from 0V to 10V, (2) falls from 10V to 4V, (3) sustains at 4V if the gate is still high and for as long as the gate is held, (4) falls from 4V to 0V. The fall times at (2) and (4) are determined by the Fall pot + assigned CV.

For (3) to work without hiccups (e.g., if one were to patch something more exotic than a gate stream into Trig), the module might need to sample and then hold the positive voltage present at the Trig input once the Fall time has completed, and then initiate another Fall stage once the signal at the Trig input has been detected to drop below the attack-triggering threshold. I’m not sure how digital modules like Just Friends and Zadar have addressed this edge case in their ADSD implementations.

That detail aside, Quadrax would seem very capable of delivering this kind of envelope, because it seems to only require a rising edge to 1.33V to trigger an AD envelope. All that one would need to do is attenuate the gate signal going into the trigger input, allowing a range of sustain levels from ~1.33V to 10V. This would entail that the module can’t produce an ADSD with a sustain stage that’s less than ~1.33V, but that seems like a very acceptable limitation for the typical musical applications of this sort of envelope.

One last thought on this – if how I’m envisioning this being implemented is feasible and sounds like the way to go, maybe it would make more sense as an alternative option for the AHR mode (maybe called “ARHR” if “ADHD” is too spicy ), since the envelope would produce an AHR if the gate signal isn’t attenuated and its height is greater than or equal to the Quadrax’s max output voltage (10V or 5V depending on the System Mode selection).

[sidereally]

+1 I would LOVE this !

[sidereally]

Does IJ team think Quadrax is capable of this ADHD?

[maceq687]

Ok, Quadrax is already pack with amazing features but how about yet another alternative one?
I was thinking about delayed LFO functionality, just like the one on some vintage synthesizers or modules like Doepfer A-147-2, Ladik L-127 or Disting mk4 (M1 mode). I believe it is already possible to achieve it setting one channel to LFO mode and another to AD or AHR and use the second to control the level of the first. In this scenario you have to use two channels to make it work and it would be nice to sacrifice just one channel for it, especially in a small case.
Unless it could be achieved using burst mode alone?