If you’re talking about that really sproingy bass plonky thing toward the beginning, then it’s actually very simple. In fact, you can make those on a subtractive synth provided it has LINEAR FM. (you can do it with exponential FM, but then you can’t keep it in tune) This is actually the simplest form of 2 operator (or two oscillator FM) You’re hearing two sine waves basically.
One is modulating the other. The first (carrier) is tuned at the audio frequency that you want. The second would be at high-ish LFO rate and up into the audio range. You can play the first with notes, and use either a sine LFO to modulate its frequency, or an operator using sine wave modulating it.
The modulator can either track the note frequency (though lower by X amount (maybe an octave or two) or it can be a static or arbitrary pitch.
You don’t want to hear the second VCO, just use it to modulate the pitch of the first.
That will get you this exact sound.
On the Digitone, you just need an algorithm that has one operator modulating the next. Like maybe the one that has two parallel sets of two. Faded all the way toward X or Y (so you only hear the one pair).
Or you can use the one with four parallel single operators, and only modulate with an LFO.
Either way, you’ll get a similar result.
The easiest way to build a patch like that, just to get used to it, would be an init patch, (sine wave) then assign a sine wave LFO to pitch, and set the depth to low values until it wavers quickly, and start playing some notes. To get it to sound more springy though, you’ll also want to change the LFO’s rate per step, so maybe use the second LFO in the random mode, and time it per 16th note to control the pitch of the first LFO.
If you want it to stay more in tune, then switch from using the LFO to using a second operator. The B-Page in the synth settings is where you can set the modulation levels. This method will sound better, but will take more experimentation to get right.
