Uhm, as far as I remember this sound is already inside the PC3-factory sounds. Just search for it. I guess it´s even named "popcorn", but I am not sure. It is a reminiscence to early but famous synth-music, a song called... well "popcorn". https://www.youtube.com/watch?v=NjxNnqTcHhg
And well, yeah, I have an idea how to create that. It´s a short sawtooth blip. Maybe some keyboard tracking with the filter and some resonance slightly up. Nothing fancy.
Well, your example is a bit different, since it seems to use a rectangle-wave instead. You can achieve this easily while not using the internal VA synth, but just the rompler waves instead. Easier to choose a waveform.

Hi
Thanks for the advice. I did search for Popcorn before posting and didn't find it in the list of stock sounds. I will try out your programming idea. I'm just learning how to do synth programming from scratch but this sounds like a fairly simple one...
Cheers
Brad

It´s difficult to learn programming the VAST engine without the background experience of programming simpler analog or rompler synthesizers. Or FM. It´s more difficult to understand the structure how a sound is done without that knowledge. And realize the difference when the VAST engine is doing something else.
There are severals ways build a signalpath with quite similar outcome or just slight audible differences, this makes it even more confusing.
Always start with something that comes the closest and uses a low number of layers. Work on one and switch off the others. This sound can be done in a single layer, but also with several more to make it sound better. Have fun!

If I remember correctly the "popcorn" program that Kaffimusic refers to is in the Kore 64 set, so if you don't have that, it could be why you aren't finding it.

Ah yeah, right. But to clarify that, the PC3 does not need the Kore to do a sound like that.

So how can I do that without Kore?

Yes, sure.
Here, check the attached file. It´s a No-Kore variant of the Popcorn sound.
Check how it is built. A ROM wave pushed through a classic analog envelope and filter section. Okay, it´s digital Rompler style, but it´s the classic analog structure. It´s a very simple one, just one layer.
Go to page KEYMAP and check the waveform I selected. Change it and check how the sound changes. On the KORE set, there was a different waveform that is placed on the KORE board. But it works okay with an internal wave, too. Sounds slightly different.
Go to page AMPENV. This is the volume envelope. Choose Dec1 (means decay 1) and rise the value (seconds). Hear how the sound fades longer after the initial trigger. Check the first parameter "Attack". Rise the value and hear how the sound fades in slowly. Welcome to sounddesign!

Hi
That is amazingly close to what I wanted. Thanks so much. I tried the adjustments and found it really easy to understand. You're a great guy. Thanks
Brad

Yes, sure.
Here, check the attached file. It´s a No-Kore variant of the Popcorn sound.
Check how it is built. A ROM wave pushed through a classic analog envelope and filter section. Okay, it´s digital Rompler style, but it´s the classic analog structure. It´s a very simple one, just one layer.
Go to page KEYMAP and check the waveform I selected. Change it and check how the sound changes. On the KORE set, there was a different waveform that is placed on the KORE board. But it works okay with an internal wave, too. Sounds slightly different.
Go to page AMPENV. This is the volume envelope. Choose Dec1 (means decay 1) and rise the value (seconds). Hear how the sound fades longer after the initial trigger. Check the first parameter "Attack". Rise the value and hear how the sound fades in slowly. Welcome to sounddesign!

KMPPCORN.P3K.p3k

Yeah, next step is to link the filter (one, there are several to choose from - lowpass is the most common one) with the (another) envelope generator (Korg language) and let it open and close over the decay. Play around with the resonance of the filter and check what it does to the sound. Especially while the filter opens up and down. Check other filter-types and listen what they do to the sound.
Then you will start to use more than one oszillator (waveform), opened up in a second layer, detune them, mix them, pan them differently and you will understand how a rompler style synthesizer works. Simplest form to create sounds.
The PC3 line can have 32 layers of that in one single sound (program). In a setup you can stack those programs 16 times. Makes no real sense, but you could.
When you start to understand and compare that to other synths then you will start to realize what power the synthesizer structure has. Others claim their 8 layers to be a big deal.