Future Sound Systems FIL4 Timbral Sculptor review

Does this ‘timbral sculpting’ tool blend the best of East and West Coast design?

  • £356
  • €398
  • $339
FSS FIL4 Timbral Sculptor
(Image: © Future)

MusicRadar Verdict

A rich and rewarding tool than can bring some analogue uncertainty to any synth sound. Why not ditch your old filter and start timbral sculpting?


  • +

    Full of analogue goodness, non-linearity and surprises.

  • +

    Very flexible routing system.

  • +

    The filter offers an audio FM attenuverter.


  • -

    Having to repatch to change the position of the VCA in the signal chain.

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FSS FIL4 Timbral Sculptor: What is it?

Future Sound Systems’ latest offering, the FIL4 Timbral Sculptor, provides a variety of timbre-shaping goodies in one handy package. On the one hand, it offers the additive qualities of West Coast wavefolding and, on the other, subtractive East Coast filtering to carve out unique sounds.

Let’s start with the filter. It’s a -18dB slope multi-mode running on an SSI2164 filter core, but rather than offering separate outputs for LP, BP and HP, the Timbral Sculptor has level controls (with CV inputs) for the different modes, allowing much greater control. The filter on its own sounds smooth and clean. It features a slightly accentuated resonance at high cut-off frequencies which lends it a 303-esque tone when modulated. There are two CV inputs: the first has 1v/oct tracking; the second runs through an attenuverter. The filter also boasts an audio FM attenuverter; inspired by the quirks of the Korg35 filter, this can provide some beautiful instability.

Moving on to the wave-folding, there are two separate folders: the first a Buchla-style Deadband switchable pre or post filter, the second a Lockhart which, along with a rectifier, sit in the resonance path. Not being a fan of squealing resonance, this at first seemed a strange choice to us. Little did we know the sonic delights that it would provide… The module is completed by a VCA circuit which can also be switched to the input or output or even used independently of the signal chain. The drive control affects the amount of wave-folding, with the VCA input providing you with CV control.

FSS FIL4 Timbral Sculptor

(Image credit: Future)

FSS FIL4 Timbral Sculptor: Performance and verdict

The FIL4 offers a great deal of flexibility over routing, but one thing that tripped us up initially is the fact that you have to re-patch inputs and outputs depending on the VCA position in the chain. No doubt this is unavoidable but it does feel a little clunky. Moving past that, on first play, the wave-folder and half/full wave rectification unleashed a maelstrom of sonic destruction. All good fun and this may be exactly what you’re looking for but we sought a little more subtlety. Once we'd got to grips with the Sculptor we soon found that the timbral palette was actually very broad.

In the best way, this is a module that revels in non-linearity, each element of the control and signal chain influences the others, making it easy to get lost in sonic exploration. Starting with a simple sine wave input, we were quickly pulling out a sound that morphed from natural woodwind to the guttural croak of a 303. Note, however, that it also plays well with complex sounds sources.

Once you’ve found an interesting sweet spot, there is plenty of room to vary the tone to keep your synth line interesting. We found subtle modulations, unusual distortions and even some 8-bit effects and strange pitch sweeps courtesy of the rectifier. It does occasionally drop into discordance or silence but this is the nature of such a beast. Like the rest of FSS output, this is all about pushing analogue electronics to the edge. It’s what drew us to modular in the first place, it’s organic and surprising and when applied subtly can be just the thing you need to bring your sounds to life. 

MusicRadar verdict: A rich and rewarding tool than can bring some analogue uncertainty to any synth sound. Why not ditch your old filter and start timbral sculpting?

FSS FIL4 Timbral Sculptor: The web says

"FIL4 is a really fun module with some great routing possibilities that set it apart from similar synth voice modules."
Waveform Magazine

FSS FIL4 Timbral Sculptor: Hands-on demos



FSS FIL4 Timbral Sculptor: Specifications

  • KEY FEATURES 18dB multi mode filter, rectifier, two types of wave folder, VCA.