Comb Filters appear to Glich Badly when Changing Frequency

[crackershaun]

The Comb Filters appear to Glich Badly when Changing Frequency. Is this a problem that Comb Filters generally have, or is this a problem with the Pigments Comb Filter? 

It even shows on the Analog Triple VCO Template if you swap the Filter to Comb.

The Combs Filter in Serum also seems Glitchy when Changing Frequency, but weirdly in a more musical way, to me, at least.

If it is a 'glitch' in the Pigments Comb Filter, is this marked down for an improvement or fix?

If a General Problem with Comb Filters, is there someone who can explain the effect, when it is often worse, when it may be less bad, and if there are any ways to better control it? 

Someone who is liking Pigments, especially the current V6 cross-grade. 

[LBH]

If you just change the filter type in the Analog Triple VCO template preset, then the FREQ for the Comb filter is set to 20 (HZ). Have you for example tried to tweak the Comb filters FREQ and KBD parameters?

Also have a look at the Mystic Pluck preset. It only run noise thru a Comb Filter to create a plucked string sound. Try to turn off the Comb filter on that sound, and then you only hear noise - no tuned notes.
Comb Filters are in good use for Psysical Modeling sounds.
This is just one example.

Please post a preset with the issue, and tell how to experience it, if you still think there is an issue. Then it's possible to understand your issue better. I have not tested everything.

Don't know if it helps, but here is 2 links about Comb filtering:
https://en.wikipedia.org/wiki/Comb_filter
http://www.moultonlabs.com/more/about_comb_filtering_phase_shift_and_polarity_reversal/


EDIT: BTW: Don't forget you also have Comb filter in the Multifilter in the FX section, and also Flanger and other effects. EDIT END

[illywhacker]

I've noticed ALL filter types glitch, especially the surgical one. Easiest to check this by loading up just a Sawtooth wave and dragging the filter frequency open and closed with your mouse. I can definitely hear artefacts/glitching/digital stepping on my system at least. I love this synth, I hope they fix this issue though. Then I'll buy it

[crackershaun]

The simplest case is the Analog Triple VCO Template with the default Mini Filter changed to the Comb Filter.

Nothing else changed.

Then the Glitching occurs when the Frequency Knob is in the process of being Moved.

The Glitching stops when moving the Frequency Knob is stopped.

By Glitching I mean a kind of scratchy gliching as if each micro-second the sound is being swapped between two very different settings instead of having smooth transitions. 

[LBH]

As a Comb filter goes thru frequencies and does reinforce and cancel soundwaves, then there will be some natural steppings. Is that what you mean. Pigments Comb filter have a huge frequence range. I don't know about Serum.

Do you know you can make very fine adjustments when using your mouse if you use rightclick or Control+click? Perhaps you move the knobs a too long range to fast.
If you use this method, do you still experiment what you call glitch?
And what if you use a modulator?

I do agree, that the Comb filter perhaps could use some more controls. It could perhaps be for limiting the Frequency range for the Freq knob, for setting FB/FW amount. And perhaps a selectable 6 dB/oct low-pass filter to the feedback.

You can also try to put in a low pass filter before the Comb filter.

At this point i can't tell if the Combfilter work as intended or not.
But it can be hard to control i agree. Also when using a 0-127 CC controller knob, as that does sound very steppy. I think it's the same with the wavetable  Especially if you what to create a sort of manual Sync Sweep effect using a controller knob.

BTW: A way to control the Comb filter sweep using mudulators that's a big part of Pigments can be seen in the preset Istambul's Market.
The presets Assault and Gigak use a modulated Surgeon filter.

I will not say this is a bug as such.
But perhaps Arturia should go thru the synth in generel for things where you might hear too annoying steps using a 0-127 CC control. In that case, it might be a good idea to add selecable ranges for a parameter, and perhaps other things - including some kind of smoothing.
A filter like the Surgeon filter does sound steppy too, when changing the setting - not when it's still.

Pigments is a great synth that sounds good. So many synth can only sound harsh and noisy. This can in addition also sound smooth and more. It has a huge usage range, and that in some cases might call for a need to have different selectable parameter ranges, even if there also is a meaning in how Pigments allready is. And then there are the taste and exspectations  of each user.
It's only in some usages, that this stepping is an issue. And in many cases there might be ways to control it, as the synth is so versatile.

Am i on the track?

[crackershaun]

I think this seems on the right track.

There is a very similar effect with Serum but for me it seems slightly more musical and less grating to my ear. Maybe it has a finer resolution for the steps?

Do you think this is an issue where in general you can't really do filter sweeps with comb filters because harmonics are being created and destroyed in a 'steppy' way that can't really be smoothed? 

It isn't something I have used before and I only noticed it by playing around with the options and controls. 

Pigments seems to encourage that in a creative artistic type way! I am enjoying it. It is NOT a Pig in a Poke!! 

[illywhacker]

Tone 2's Electra 2 Comb filters sound really great and smooth. I can't notice any digital stepping or glitches in sound as you move the Filter Frequency knob on Electra 2. So Arturia should be able to achieve the same result

[LBH]

I think this seems on the right track.

Good.

There is a very similar effect with Serum but for me it seems slightly more musical and less grating to my ear. Maybe it has a finer resolution for the steps?

Perhaps. I don't know how it's designed. I don't have Serum. You tell me. Can't you hear it. Perhaps it even can have a larger range, but having the range in the upper frequency spectrum and cut at some point at the lower spectrum. Perhaps not. Can't tell.
What does musical mean in this?
Perhaps there are things Pigments Comb filter can do, that Serums can't do at all?

Do you think this is an issue where in general you can't really do filter sweeps with comb filters because harmonics are being created and destroyed in a 'steppy' way that can't really be smoothed? 

I'm saying a Comb filter work in a way where frequencies is being affected. Have you read the articles i posted?
But i don't know. I'm not a technician. I assume there are ways to smoothen the stepping so it more glide thru frequencies.

And i'm also saying, that it can be hard to manually do sweeps in the full range of Pigments Comb filter without hearing stepping.
But you can also add modulators in Pigments to control the sweep. Try it.

Have you had a look at the presets i mentioned in my previous posts? Can you hear bad stepping in those?
The presets i mention can help.

Other Comb filters might only use the high range spectrum and other things to make a one trick filter sweep pony, that perhaps is no good for other things. And perhaps the sweep is even poor even if it might be smooth when done manually. And keep in mind, that Comb filters is about much more than making a manual sweeping effect.

I don't think, i can explain it better, than i allready have tried to in my previous posts. So please refere to them.

[LBH]

Perhaps this also explain.

I have attached a test preset (login to download) where Macro 1 named Comb Freq is controlling the Comb filters Frequency. Use the macro instead of the Freq knob. It's sort of a way to control the range.
Things like this can be used to create manual sweeps.
Also try different Gain settings for the Comb and also change the other parameters including the mode.

I think that work great. But it's not as easy as just using the Filters own Freq knob. What do you think.