Review: VirtualCZ by Plugin Boutique + free soundbank

By | 2016-11-07T13:46:46+00:00 April 2nd, 2016|review|

Recently, I had the privilege to spend some time exploring the VirtualCZ software synthesizer from Plugin Boutique, and I thought it would be a good opportunity to do a review of this little gem.

A short introduction of the synth

In the 1980’s synthesizers around that time were almost exclusively dedicated hardware devices. Synthesizer technology began to move from analog to the then upcoming digital technology. It was the time of iconic digital synthesizers like the Yamaha DX7.

At that time, Casio was most known for its series of home keyboards and had stepped into the professional synthesizer market with its Casio CZ-101 synthesizer, followed over time by its successors – the CZ series.
Being affordable and quite capable of producing good sounds that were full of character, the Casio CZ series became quite a success.
In the late 1980’s the manufacturing of the CZ series ceased production.

The CZ series were digital synthesizers which made use of a synthesizing technique called “phase distortion”. This technique has similarities with the more complex frequency modulation synthesis technique which was used in synthesizers like the Yamaha DX7.
Today I’ll review Plugin Boutique’s VirtualCZ which is a software emulation of the CZ series of synthesizers.


The user interface of VirtualCZ has a kind of retro look which clearly is a nod to the original CZ synthesizers. In my opinion it fits the synthesizer well. The different functions of the synthesizer are nicely grouped together in separate sections on the user interface.


VirtualCZ uses a synthesis technique called “phase distortion”. It utilizes two “lines” in which both have a digital oscillator producing a sine wave. By modulating the phase of these sinewaves we can produce different waveshapes much like the well known saw, square, pulse, etc.
With VirtualCZ you can select two waveforms per oscillator. One for each alternating cycle from the oscillator. The selected waveforms are the resulting waveforms which are produced by modulating the phase of the sine oscillators. VirtualCZ knows eight waveforms: sawtooth, square, pulse, double sine, saw pulse, reso1, reso2 and reso3. The “reso” waveforms are hard-synced sine waves with a sawtooth, triangle or a trapezoid envelope. They give a more sharp sounding result; a bit similar to using a resonant filter.

By turning up the DCW knob you control how much phase distortion is applied, which in effect alters the resulting waveform. The base waveform when the DCW knob is down, is a sine wave. When the DCW knob is fully up you’ll hear the waveform(s) you selected for that “line”. When the DCW knob is somewhat open, say, in the middle, you’ll hear a result in between the basic sine and the selected waveform(s). This DCW setting than can be used as an offset for further modulation with the envelope generators of the synth. The result of turning up the DCW knob sounds something like opening a filter on a subtractive synthesizer.


VirtualCZ GUI

Furthermore, the oscillator section has a switch to enable and disable the phase reset on the oscillators which can be useful in the monophonic mode of the synth. The standard setting is on phase reset. This gives a more “punchy” and predictable sound like you’d want for a tight and punchy bass.  By switching the phase reset off you’ll get a more mellow sound. The two “lines” of the synth can be mixed in 1, 2 and 1+1/1+2 which of course, adds nicely to the sonic palette the synth can generate. To bring some more sonic variety to the table there’s a modulation mode switch which you can enable to “noise mode” or “ring mode”.

“Noise mode” modulates the pitch of the second line in the mix with a random noise function which adds some noise to the sound, or more accurately – will give the sound a more noise-like character. Ring mode applies a ring modulation effect to the signal which can generate some nice metallic timbres.
When using two lines mixed there are some controls for detuning the second line in the mix (octaves, semitones and some finetuning).

The envelope generators come in two flavors. There’s an ADSR mode which gives you the more traditional ADSR envelope generators to use, and there’s the MSEG mode which brings you the power of Multi Stage Envelope Generators as used originally on the CZ synthesizers.

While the ADSR envelopes are easier to program, and might offer a good start on programming the synth, the MSEG’s offer the most flexible control over the modulation. The 8-stage MSEG’s are capable of more complex modulation patterns and thus can add to more evolving and finetuned sounds. In MSEG mode the EG’s can be set to loop as well.

Each line has three envelope generators (ADSR or MSEG), one for pitch modulation, one for modulating the amount of phase distortion applied, and one for the amplifier. To bring some extra life to the generated sounds the EG’s are equipped with knobs to regulate the depth of the modulation, and the impact of the note-on velocity to the modulation depth.
Except for the pitch modulation section, the EG’s have a knob to control the key follow parameter too.

VirtualCZ offers a 32 voice polyphonic mode, a mono- and a legato mode. When using the synth in mono or legato mode you can enable the unison feature with a maximum of 8 voices. Furthermore, there are knobs for portamento, octave shift, tuning, bend range for pitchbends and a master volume knob.
There’s also a scaling section which gives you the opportunity to finetune the velocity and aftertouch response curve if you wish. The synth supports both “channel pressure aftertouch” and “polyphonic aftertouch”. You can choose to route the aftertouch to DCW, LFO and AMP which nicely adds to the playability of the sounds.

There’s a vibrato section on the GUI which can be used with a tempo set on the synth, or can be synced to the tempo of the DAW. The vibrato module offers a variety on LFO waveforms to set, and thus can be used to not only apply vibrato, but also more wacky modulations with for instance the s+h (sample & hold) and noise settings.
It should also be mentioned that the synth has an onboard chorus module which can be set to two modes. One is a nice clear and lush sounding chorus modelled on the classic Roland Dimension D chorus. The other is the traditional CZ type chorus which has a character I’m personally very fond of.

There’s also a pan knob which controls the pan width parameter. This is used to create a nice spread of the sound in the stereo field, and thus brings some space to the sound.

The synth supports loading custom tuning tables in the “.tun” file format which is a nice feature for musicians who like to experiment with what is referred to as “micro-tonal music”.

But how does it sound?

Well, I have no experience with the original hardware CZ synthesizers, but from what I heard when listening to demo’s being played on the original CZ synths; it captures the sound of it pretty well.

I must say that this synth has a lot of character. It’s not a very deep synth, but there’s certainly enough to explore. You can create some great sounds with it. It is easily capable of producing punchy basses, thick leads, and lush evolving pads.


Personally I enjoyed the synth very much. It’s not overwhelming in features, so you can get going pretty fast. The MSEG’s though might need some getting used to. But once you get the hang of that you can have a lot of fun with it and create good sounds fairly quick.

The synth contains almost 300 factory presets that were crafted by the developer of VirtualCZ, Oli Larkin, sound design veteran Don Solaris and AbstractCats, and offer good variation. You’ll find bread and butter type sounds here as well as more “out-of-the-box” type sounds.

One thing that could be improved is the user manual. It has enough information to use the synthesizer but it also seems to lack more in depth information that might be valuable for some. It seems that the developer recognized this because there’s a “coming soon” section in the manual for a more in depth chapter about the architecture of the synth and the Phase Distortion synthesis technique.
A thorough and finished manual would be the icing on the cake here.

As for value for money; the price of VirtualCZ is certainly fair. I think the synth is definitely worth it.

If you are already using VirtualCZ…

I created a small package of 15 presets for VirtualCZ specially to accompany this review on

You can download the pack here:

More info:

VirtualCZ by Plugin Boutique

About the Author:

Frank Zuidervaart
Frank Zuidervaart is a dutch synthesizer sound designer under his label “Krezie Sounds”. As a musician he likes to play some guitar as well (love the sound of a strat!). Furthermore he is an ICT professional and if he has some time to spare loves to play retro consolegames ("yeah, I’m a sucker for videogame nostalgia"). Visit Krezie Sounds for free and commercial soundbanks for AAS Ultra Analog VA-2, Hive, Image-Line Harmless and VirtualCZ.

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