Analog State Variable Filter




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Analog modeled State Variable Filter (LPF, BPF and HPF modes). 2 or 4 poles.

No FFT algorithm here, but true analog components emulation.

MIDI notes input to set the cutoff frequency and/or trigger the envelope.

2 VirtualCV inputs for analog-style parameter automation.

Internal audio quality is 64 bit double precision with 4x upsampling frequency for the filter section.

MIDI-syncable LFO modulator with stereophonic phase adjustment parameter.

SSE2 CPU optimization.

Dry / Wet mix parameter.

Audio input envelope follower for cutoff or resonance modulation.

Sidechain input for cutoff or resonance modulation.

Unique analog modeled soft clip algorithm.

Left/Right LED Metering.


See for yourself what the SVF-42 is capable of.

This audio/video demonstration has been captured live (no track freezing what so ever) on a 12 tracks song with four SVF-42 instances running.


Traditional parameters automation has been used along with VirtualCV automation.


This is only one out of the infinite combinations and creation the SVF-42 can bring you to.

Experience it!

Features in details

The SVF-42 is an analog state variable filter emulation.

The main difference with similar competitors plugins is that we didn’t use FFT algorithms.

Instead, we carefully modeled every electronic component of the original circuitry. The following diagram describes the electronic circuit emulated by our core algorithm (filter section only).

This approach implies greater use of available computing power, but an audio result of much better quality and more accurate.


SVF stands for State Variable Filter. While 42… well, some may say that it is the Answer to the Ultimate Question of Life, the Universe, and Everything, but some others may also recognize a reference to a real piece of hardware (an analog state variable filter!) that existed in 2000 - 2001, and that inspired a little bit the development of this plugin.


That actual real-life hardware used a chip from Texas Instruments™, the UAF42.

Although the electronic circuit is similar, this device lacked of personality in the audio result of the filter itself, but the functionalities around the filter, like a LFO, and an externally triggered envelope generator, made it a hit and it was used a lot by techno producers, as well as hip-hop musicians.

With the SVF-42, we wanted to create a quality filter that would have a warm analog sound, EXTREME resonance ability, along with functionalities adapted to modern music production techniques.


All the parameters are driven with simulated analog level behavior thanks to our AnalogValue technology.

The filter itself isn't your average filter. We spent a lot of time adjusting with passion every internal parameter (or let's say every virtual electronic component !) to obtain the best sounding filter we could achieve.

The base cutoff frequency parameter range from 16 Hz to 16 kHz. Then it can be modulated with an envelope follower on the audio input, or from a sidechain input (see your DAW software documentation to find out how to route audio signals to a secondary VST audio input). The LED ring around the cutoff knob will indicate the actual modulated value while the envelopes LEDs are brighter on higher input levels.

A LFO with 6 waveforms, syncable with the host's tempo, and with a stereophonic phase adjustment parameter, will allow you to do all the wah-wah-wah you'll need !

The resonance parameter can be set so extreme that we had to implement a warning sign that lights up when the output level can become too hot, depending on the number of poles used. It can also be modulated with all the same sources previously described.


Nowadays, DAW softwares all offer many parameter modulation abilities,

but unfortunately the results are often too mechanical. This is why we developed the VirtualCV technology. Basically, VirtualCV inputs are like VST parameters but only accessible through your DAW’s automation interface. You can use any possibility given by your DAW or external virtual devices, such as MAX4Live EXT for example.

This automated parameter is then converted by VirtualCV in a virtual 0 to 5 VDC analog control voltage signal, modulating respectively the cutoff frequency or the resonance parameter of the filter, in a much more analog-ish way, eliminating hard steps and avoiding bad sounding transitions.


If you need a more precise way to control the cutoff frequency, you can also use MIDI notes. Simply route one of your DAW’s MIDI track to the SVF-42 (see your DAW’s documentation on how to route MIDI signals) and it will respond to MIDI notes by setting the cutoff frequency to the appropriate value, with a glide speed that can be adjusted with the envelope attack time parameter.


At the output stage, the SVF-42 is equipped with a quality stereo LED meter, and an output gain knob. But what you’ll notice first is probably that SOFT CLIP button !

As the filter section can deliver such high audio levels, the most natural and realistic way to limit these was to implement a unique high quality soft clip algorithm.

You can obtain subtle warm analog clipping, or heavy distortions. Just put as much resonance and output gain as you’ll need to obtain the desired sound!


Need any support ?

or head over Twitter to ask your questions.

Acid, Rock, Techno, Hip Hop, Fidget, Dubstep... one filter!

CV in a plugin!

Overdrive it!

MIDI control.

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