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Review of Polyvibe effect (Windows / MacOS) by Blue Cat Audio


Blue Cat’s PolyVibe is a complete re-creation of vintage “vibe” pedals, based on original designs and taking them several steps further for the 21st century.

With a couple of twists and innovations, the plug-in can simulate many kinds of “vibes”, chorus, phaser, rotary or wah/vocal effects, while keeping this particular vintage flavor that is so typical to “vibe” pedals.

Polyvibe is available from Blue Cat Audio in Windows and MacOS versions and is typically priced at $79.

A brief overview of Uni-Vibe

The Uni-vibe was designed in 1968 by Shin-ei, a Japanese Company and was subsequently bought by and is a registered trademark of Dunlop Manufacturing Inc.  It was an effect designed to replicate a Leslie rotary speaker.   It didn’t do that particularly well but what it did do was create a modulation effect that is similar to a phaser and similar to a chorus but isn’t either of those, it is uniquely different.

An overview of the circuit is shown below.  Essentially the input signal passes through a pre-amp into four allpass filters in series.  These filters allow all frequencies to pass through but when the output of each pair of allpass filters is mixed with the original signal,  frequency notches are created where these phase shifts intersect.  The notch location is modulated by an LFO which sweeps the allpass filter centre frequency.

Although a phaser uses the same arrangement of allpass filters and LFO, there are some key differences –

  • Phasers tend to match the centre frequency of allpass filters in pairs.  In the electronic circuit this is determined by capacitor value which for reasons that no-one seems to know are somewhat arbitrary in a Uni-vibe.  This results in more spread in the notches.
  • Phasers directly use an LFO for modulation which is effectively causing a change in resistance in the electronic circuit. A Uni-vibe uses the LFO to drive a traditional (incandescent) lightbulb coupled with four light dependant resistors whose resistance varies with the brightening and dimming of the bulb thus changing the resistance in the electronic circuit.
  • A Uni-vibe sends part of the input signal directly to the output buffer and the effect has a switch which allows you to select between a chorus effect (mixes the original and processed signal) or vibrato (processed signal only). 

Because of this analog element to a Uni-vibe – especially coupled with the fact some components have changed over time, are now hard to get hold of and/or you may need to modify original circuit values for modern components – they are notoriously difficult DIY builds and pedals tend to be expensive.  Used pedals typically cost around  £100 – £400 or much more for some boutique models.  Many guitarists don’t consider a pedal to be a true Uni-vibe if it doesn’t have a bulb and LDRs.  That said, there are some much cheaper digital pedals available and some of these do sound very good. 

Polyvibe Overview

The GUI has a 60’s psychedelic vibe and is split into 4 sections – the top part is the main toolbox giving access to the main settings and options.  The effect settings look like a guitar pedal and are split into 3 sections – effect mode and intensity ; filter shape;  LFO.

What I really like about Polyvibe is that it is easy to use and sounds great too.  The interface is deceptively simple, hiding the complexities of the effect which provide a huge variety of sounds.  It’s highly flexible and provides versatility that you wouldn’t find in a single guitar pedal.

It comes with about 100 presets that give you a huge range of sounds and/or starting points and it also has the innovative tonemap feature which gives a visual representation of different presets, you can navigate through them or create new tones by placing the cursor in between several presets. 

Polyvibe in-depth

Polyvibe has 3 modes –

  • Classic – Recreates the classic vibe effect and its soft notches;
  • Reverse – The phase shift effect is reversed causing peaks instead of troughs.  This creates vocal / wah effects;
  • Phase – Creates moving phase shift with a different type of filter to mix with the original signal creating other chorus / phaser tones.
This section also has a modulation LED showing the status of the LFO and Intensity which controls the intensity of the filter and hence the intensity of the effect.

Filter shape controls gives a lot more control than you’d typically find in a pedal.

Freq allows you to control the frequencies affected. Positive values affect to higher frequencies and negative values apply the effect to bass frequencies.

Bandwidth adjusts the bandwidth of the filters which will affect the notches, peaks or dephasing depending on the mode selected. 

Separation of peaks or notches. When set to zero the filters act as a single filter with a stronger effect.

Motion has a normal setting where the filters move in the same direction or opposite mode where they move in opposite directions and may cross over each other.

The LFO controls offer a lot of modulation options.

You can sync to host or set the rate independently.

Depth can be varied with a zero setting corresponding to static filters.

Swing adjusts the shape of the LFO with non-zero values resulting in an asymmetric shape which creates a swing effect.

Stereo controls the amount of phase shift of the LFO between left and right channels to create a stereo effect.

Dephase adjusts the alignment of the LFO with your DAW’s timeline.


This is a very cool feature which can be seen on some Blue Cat Audio plugins.

What it allows you to do is load several presets that are presented as a 3d space.  If you want a sound that lies between the presets simply click in the space between them and Polyvibe will adjust the settings and create a new preset for you. It’s an incredibly useful feature that allows you to quickly create sounds if you’re struggling to do this from scratch or by tweaking a preset.


Polyvibe is brilliant software.  It’s incredibly versatile and produces that classic Uni-vibe sound – along with a huge number of phaser, wah, chorus and flanger type sounds – in one easy to use plugin.  If you consider the overview discussion of the Uni-vibe above, you can see just how much control and sound options are offered, a lot more controls and tweaking options than you would find in any single pedal.

The sound quality is excellent too, as well as being easy to use there are tonnes of presets and the innovative Tonemap feature where Polyvibe will create a new preset for you simply by clicking between presets on a visual map makes it incredibly easy to find the exact sound that you want.

Whether you want a subtle phase, extreme Uni-vibe, chorus or auto-wah type effects this can do them all.

For example. here are a few demo sounds.  I’ve kept it simple and used Polyvibe, Shibalba amp (Audio Assault) and Tverb (Eventide).  I’ve mixed using Fabfiler effects – Saturn, Pro-Q3 and Pro-L.  Initially Polyvibe is bypassed so you can hear the basic sound and then Polyvibe is enabled.  The sequence of effects is fast univibe, classic deep Uni-vibe, fast auto-wah, a swing effect and tremelo type effect.

But it can also produce more complex sounds, this is a full shoegaze type of sound, it’s the same basic setup as above but also uses Blackhole and H949 Dual by Eventide and TSE R47 by TSE Audio.

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