Amp envelope clicks / pops

I’ve noticed that when a sound uses a short attack time on the amp envelope there’s often a noticeable click / pop (especially noticeable when cutoff is low). I imagine this is just your standard zero-crossing issue - would there be a way to implement the oscillators starting at a zero point with each key press to combat this? (like you would see on the Moog Sub 37 with the KB RESET feature for the oscillators)


Just bumping this - has anyone had the same issue?

Yep, me too. It’s very ‘blippy’ when attack is set short. I thought I had solved it the other evening by turning off portamento. However - just tried it and that’s not the case!

I think, everybody has this, but it’s not an issue to everybody.

First you should know: Each abrupt start of a tone (even a sine wave starting at zero) contains overtones which represent as an audible click (same at the end!). Of course it’s worse if the wave starts (or ends) at its amplitude maximum.
And if you use Super DDS1, than you have 7 Oszillators starting exactly in phase… running slowly out of phase, what results in a lower summing amplitude, what makes it even worse.

If you would filter out these overtones, you would get a sine with a short (several oszillations) attack and release phase.
Same you could get if you use a VCA envelope with a short attack (and release) slope.

As I recall, this was intentional when UDO released firmware 0.26 to allow for really snappy attacks which are sometimes useful when designing percussive sounds.

Here it is from the firmware release notes:

Faster Amplitude envelope attack times. An extra 15% of travel has been added at the bottom range of the ENV2 ATTACK slider reducing minimum ENV2 attack times without affecting stored patches

So if I remember correctly, the bottom 15% of teh Attack travel has been reconfigured and if you want to override it just raise teh attack time about 15% and it will be like it was before.


I have exactly this issue as well and came here to ask about it. I was noticing that I was having to set the VCA attack a bit longer than I would have liked to get rid of it on some patches.

Also, some of the factory patches (bank C patch 4 is a good example, as are d3 and e3) have some clicking/popping when they seem like they shouldn’t (they are like slower pad sounds).

It sounds like the clicks/pops may just be the nature of the beast, and maybe some of the factory patches are doing it because they increased the ENV2 attack 15% but did not change the factory patches to account for it?

But just to be sure, would anyone mind checking their factory preset C4 to see if it has clicks/pops for them as well?

Yeah I think this is a feature. Personally, I love it! I haven’t noticed it at all in patches that are meant to be slow and long, but it’s very useful for bass and percussive sounds.

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I actually went to check out C4 and I must have deleted that preset by accident -_-. Are there any other factory presets I should check out?

d3 and e3 are the same although not as pronounced

I checked them out, I was able to notice a slight click on d3 and nothing on e3. I think that’s pretty normal and personally I like a bit of click cause it gives the sound some character. I’m running the latest firmware though, so maybe double check that you are on 0.26, otherwise just try increasing attack a little bit and you won’t hear that click!

Thanks Mannerow!

It has its quirks, but I have to say that the super 6 is the best synth I have ever owned. I was having a really hard time finding an analog polysynth that I liked so I decided to give this hybrid a go and I am so glad I did!


No problem.

Agreed, this synth is amazing! As far as the clicks, it might just take a little getting used to if the other synths you are using have slower attacks. At the end of the day I think it’s better to have a really quick attack and be able to make it longer, than being stuck with a slower attack and not having that option.

Yup, there’s a few bugs, the main one for me being that the sequencer doesn’t sync to well with my daw. It syncs up but doesn’t reset the sequence when I stop and start Ableton. Other than that, I’m looking forward to being able to use USB midi… Since the firmware is only v0.26 I think it’s safe to say this will be fixed pretty soon

Just checked the patch settings for D3, C4 and E3.
They all use ENV2 for VCA control with the Attack slider at the third (thin) line, which is a little too low to suppress the “note on click”.
If you just load that patch and move the ENV2 A slider to the 6th thin line from the bottom the click should disappear without any noticable attack delay.
And if you like this, just overwrite the factory patch. Its your synth.

Thanks so much for checking for me, I was just wondering about typical behavior and it sounds like that is how it is so I am a happy camper!