Sounds like: A pure noise sweep with no pitch, opening or closing like a whoosh.
A pure filtered-noise sweep, no pitched oscillator at all — the filter itself moving from closed to open (or vice versa) is the entire sound, a foundational transition element.
Open this patch in the interactive PatchpadDigitone II's WAVETONE machine (select with FUNC+SYN). Both oscillators are at LEV 0, so the sound is pure noise from page 3 (NLEV 100, TYPE GRAIN, CHAR 0 = white noise, wide band). The filter movement is the entire sound.
SY RAW's NLEV pushed to its maximum is the closest real noise source on Syntakt's digital tracks, with WAV2 silenced (LEV2 0) to keep the tone as noise-dominant as this machine allows -- a small amount of WAV1's own tone is still present underneath, since SY RAW has no fader to fully silence its base oscillator. FLTR PAGE 1 sweeps open over the rise via a long ATK and strong positive ENV.
Summit's MIXER has a real dedicated Noise oscillator, used here as the entire sound with Osc 1 silenced. FILTER's SOURCE/ENV DEPTH route the Amp Envelope into the filter cutoff too -- one long-Attack envelope shapes both the amplitude fade-in and the filter sweep together, holding at full Sustain once open rather than falling away.
Osc 1 is Noise: Wave is the noise Type (particle through white to metallic), Timbre is the Rate and Shape is the Balance with a tonal wave. Noise is the entire sound here, no pitched oscillator involved. This is the documented cross-reference mechanism for filter movement on MiniFreak: since there's only one Envelope (hardwired to the VCA), routing its output into the Filter's own ENV/VELO knob gets the cutoff to open in step with the amp fade-in, with no second envelope required. Values are on MiniFreak's native 0-100 scale.
No dedicated noise source exists on Typhon -- a heavily detuned VCO pair (wide TUNE 2 offset) is a genuine approximation, not a true noise generator. FILTER ADSR and AMP ADSR share the same long ATTACK so the filter sweep and the amplitude fade-in move together, holding at full SUSTAIN once open rather than falling away.
Hydrasynth's MIXER has a real dedicated Noise generator, used here as the entire sound. Envelope 1 (pre-wired to Filter 1) and Envelope 2 (pre-wired to the Amp) share the same long Attack so the filter sweep and the amplitude fade-in move together, holding at full Sustain once open.
Same noise-source considerations as Filtered Noise Pad: Digitone II (WAVETONE noise), Syntakt, Summit, MiniFreak and Hydrasynth (firmware-dependent) use a real noise source; Typhon approximates it.