Frap Tools CUNSA: Chasing the ‘Liquid Filter’ Grail

The video opens with a clear statement: the Frap Tools CUNSA isn’t a filter with a single, signature sound. Instead, it’s designed as a shape-shifter, offering a broad palette of tonal characters. This flexibility is central to the module’s appeal, allowing users to sculpt everything from aggressive resonance to subtler, more nuanced textures.

Rather than chasing a fixed idea of ‘classic’ filtering, the CUNSA invites exploration. The presenter notes that, while a stereotypical ‘liquid’ filter sound might not leap out immediately, it’s well within reach for those willing to dig into the module’s parameters. The emphasis is on adaptability—CUNSA can be tamed or unleashed, depending on how you approach its controls and signal flow.

Central to CUNSA’s versatility are two controls: the character knob and the amplitude parameter. The character knob determines how the filter responds to overload, shaping everything from soft clipping to more saturated, aggressive behaviour. This isn’t just a cosmetic tweak; it fundamentally alters the filter’s response, especially when resonance is in play.

Amplitude, meanwhile, governs the level of the signal hitting the filter’s input VCA. The presenter stresses that even small adjustments here can yield dramatically different results. In fact, they claim that in most cases, tweaking amplitude has a more profound effect on the filter’s personality than any other parameter.

Together, these controls allow for deep sound exploration. By reducing amplitude and dialling back the character knob for maximum soft clipping, the CUNSA can be coaxed into a much more ‘liquid’ territory—smooth, resonant, and free from harsh saturation. The interplay between these two parameters is at the heart of the module’s ability to morph its sonic identity.

The video moves from theory to practice with a series of patch demonstrations. Starting with a simple sawtooth wave into the filter, the presenter shows how adjusting amplitude and character transforms the sweep from aggressive to fluid. Switching between 12 dB and 24 dB per octave slopes further refines the effect, with steeper slopes lending extra focus to the cutoff movement.

To mimic the classic ADSR envelope—often key to those syrupy, expressive filter sweeps—the presenter uses a clever trick with the Frap Tools Falistri. By duplicating a gate signal and patching it into two Falistri channels (one transient, one hold), they construct a composite envelope that approximates ADSR behaviour. This approach allows for precise control over attack, decay, sustain, and release, even without a dedicated ADSR module in the rack.

The demonstration continues with envelope modulation routed to both filter cutoff and amplitude, showing how careful envelope shaping and modulation depth can push the CUNSA into unmistakably liquid territory. The result is a sound that’s both dynamic and unmistakably ‘wet’, with resonance and movement reminiscent of classic Roland filters but with a distinctly modern twist.

The presenter wraps up with some practical advice for getting the most out of the CUNSA. One key tip: resist the urge to max out every parameter. Sometimes, the most musical results come from subtlety—modest input levels, restrained modulation, and careful listening. This approach helps maintain clarity and avoids overwhelming the filter’s character.

For those seeking extreme stereo or quad-filter effects, the video suggests setting all filters to 24 dB per octave, engaging combo mode, and patching identical signals through each channel. With envelopes dialled in just so, the CUNSA delivers a lush, liquid stereo field that’s both immersive and highly controllable. The takeaway is clear: with the right patching and a bit of finesse, CUNSA can deliver everything from polite ripples to full-on liquid cascades.