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Author Topic: Granular synthesis question  (Read 937 times)

mesayre

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Granular synthesis question
« on: January 05, 2023, 04:36:20 am »
I have recently picked up pigments and love this synth a lot.

However, I have a question about the granular synthesis capabilities. In some other granular synths it is possible to have the grain frequency (what pigments calls density) track the keyboard pitch, so that the onset of the grains actually becomes the fundamental frequency of the note. It becomes a kind of amplitude modulation with the grain window determining how much of the source sample's spectrum comes through. In at least two plugins I use (Halion, Absynth), this is the default behavior. But I can't figure out how to do that in pigments. Is it possible?

Thanks

LBH

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Re: Granular synthesis question
« Reply #1 on: January 05, 2023, 06:58:29 pm »
Hello,

Which Parameter in Absynth do you refere to?

You can modulate Pigments parameters whith modulators. That include the KBD modulator. If you modulate the Granular Density parameter with the KBD modulator, then the Density change according to the amount of modulation and will be different for individual notes depending on the note you play.
Is that what you mean?

mesayre

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Re: Granular synthesis question
« Reply #2 on: January 06, 2023, 04:47:25 am »
Thanks for the response. Here's what I mean:

Assume that you were to select a very short grain duration (in the 1-10ms range). When grains are that short, the pitch is determined by the density parameter rather than by the pitch content of the underlying sample. Ideally, you could make the density track keyboard exactly such that pushing C4 on the keyboard yields a grain density of 261 Hz. This then allows for some interesting effects since modulating either the pitch of the underlying sample or the shape or length of the grain window causes some intriguing timbral changes.

I went back to look and it turns out I'm misremembering about Absynth, but Halion definitely offers this feature. I suppose I can just keep using that but I much prefer the UX and workflow in pigments.

In pigments, I know that I can modulate the density parameter with a keyboard modulator, but I don't see a straightfoward way to make that modulation actually correspond to the key that I'm pressing. I have tried tweaking it by ear, but I'm stymied by the fact that the density tops out at 250 Hz, no matter what modulation is added.

I've attached a preset I made to demonstrate. I have manually set the density to 65Hz (approx C2), and if you wiggle Macro #1 it will lengthen the grains and allow the sample to emerge at the played pitch.




LBH

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Re: Granular synthesis question
« Reply #3 on: January 06, 2023, 02:21:32 pm »
The Density parameter is setting the rate of the grain. When you have TUNE Key tracking activated for the Engine, and if you set the Granular modules random Grain Pitch parameter to zero, then each grain will be determined by the played notes.
(The Pitch Bend can be used to bend the pitch +-3 Octaves.)
But too short grains will not be long enough to determine the excact pitch.

If you in your example deselect pitch Key tracking for the Engine in the TUNE section so the keys does'nt have any pitch effect, and also set both the Start and the Pitch parameters in the Granular module to Zero, then one will only hear the pitch effect the Grain Density/ Rate apply. If you set the Density parameter to 220 Hz, then you will get a A3 and 100 Hz about A2. But i'm not sure other rates will match.
Yes - You will only have the pitch range the Density parameter allow, when it's changed.
The Grain size have an impact on the sound.

I don't know what Halion excactly does, if it's different from this. Is there an example in a video somewhere?
Is the difference the Grain Density/ Rate range only? I can only see it has a percentage speed setting, if that the Density/ Rate. It's not in Hz.
It also have something with Zone pitch and such, but i don't know what that section does. I know nothing about Halion. I don't have it.

mesayre

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Re: Granular synthesis question
« Reply #4 on: January 06, 2023, 04:43:37 pm »
Halion sets the frequency of the grains as a multiple of the keytracked pitch, instead of in Hz. Somewhat confusingly, they call it "Duration". I've circled the relevant knob in the attached screenshot.

As you can see, the lowest setting is 1. Increasing it by powers of 2 yields lower octaves of they key you are pressing. Setting it to any other value gives inharmonic sounds, but that still track the keyboard (unless you turn keytracking off). Keep increasing that multiple value and eventually the grains become long enough that the frequency of the underlying sample predominates. It also varies as you go up and down the keyboard since lower notes then have longer grains.

There's a nice explanation of this in this video:
https://youtu.be/gcGTBcDiGYQ?t=136

I don't think Pigments can do this. I may submit it as a feature request. 

LBH

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Re: Granular synthesis question
« Reply #5 on: January 06, 2023, 07:18:52 pm »
Thanks for the video and further explanation.
Yes you can try a feature request.

If note pitch can set the rate/ density/ frequency of grains, then that can become a lot of grains. How is that hitting on the CPU?

mesayre

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Re: Granular synthesis question
« Reply #6 on: January 08, 2023, 03:32:19 am »
Halion's granular engine doesn't use much CPU in my experience. However, it is only triggering a max of 8 grains at a time. It also doesn't have Pigment's window shaping capabilities—Halion offers half a dozen or so grain window shapes but doesn't allow one to change them.


LBH

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Re: Granular synthesis question
« Reply #7 on: January 08, 2023, 05:43:11 pm »
Thanks for your info about Halion.

 

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