Dynamics And Fidelity Control in Illusion v1.2

By 8th October 2021October 13th, 2021No Comments

Illusion v1.2 introduces a pair of dynamics processors that are ideal for use in contemporary reverb production techniques that call for compression or ducking – but read on to find out why Illusion’s processors can do so much more than a side-chained compressor ever could in your DAW!

The new version is free to download now for all Illusion owners or you can pick up a free 14-day demo.


Illusion now has access to a compressor and a ducker (i.e. a compressor side-chained to the input signal), and some additional controls to reduce the fidelity of the generated reverb for those of us that enjoy an occasional glance towards the old-school lo-fi side of reverb.

The new features in summary are:

  • Compression which can be applied to one of the following signals:
    • Input
    • Reflections
    • Reverb
    • Reverb + VLF (very low frequency reverb)
    • Wet (reflections, reverb plus VLF)
  • Ducking
    • Reflections
    • Reverb
    • Reverb + VLF
    • Wet
  • Bit depth (crusher)
    • Input
    • Reflections
    • Reverb pre (applied before the engine)
    • Reverb post (applied after the engine)
    • Output (wet + dry)
  • Enhanced control over brick wall low pass filtering

We have also addressed a small number of compatibility issues in Windows 11.

New Features

Read on for more details about the different areas of the update.


Using compression or ducking (side-chaining a compressor inserted after the reverb with the dry signal) in Illusion allows you to control the dynamics of a reverb in specific parts of the reverb engine. That could be the input, the entire wet signal, just the reverb, just the reflections, or some combination of these. Illusion v1.2 provides many compression and ducking isolation options to allow greater control over what parts of Illusion have dynamics applied to them.

Ducking a the reverb can often increase clarity of a performance during a vocal phrase because there is less competition in the mix for the vocal, but then when the singer takes a pause the reverb level can quickly recover allowing the reverb to move in to fill the space. This means much ‘wetter’ reverbs can be tolerated because it doesn’t overwhelm the mix when the focus should be on the performer. Intelligibility is improved greatly with little effort from the producer.

The trouble with just running a compressor (with side-chain for ducking) over an entire reverb as a mixer insert effect is that it drags down the early reflections as well. This creates collateral damage. I am a firm believer that well-designed reflections enhance the spatialisation and realism in a crucial way, so pushing these down along with the reverb tail during a dry phrase usually isn’t very good news as you can often lose the beneficial effect of the reflections entirely. Reflections rarely compromise intelligibility, so it is good to retain them at their full level while the reverb is subject to dynamics processing.

That’s why in Illusion v1.2 you can now selectively compress or duck the reverb signal and leave the reflections at full volume. You will get all the benefits of the reflections, and increased tail clarity during phrases or busy moments by pushing down the late reverb until the mix has the space to return.

You may be familiar with reaching for the reverb onset controls (e.g. shape and spread in a Lexicon or envelope controls of Reverberate 3) to help control the envelope of this crucial region, but it’s helpful to let a ducker do the work for you so it can react to the level of the music.

While ducking is great for increasing clarity you can also creatively compress a reverb tail in many ways. For example by using a fairly low threshold, a large ratio value, a moderate attack and a slow release you can achieve a kind of non-linear reverb which holds steady for a period of time while the ducker works to compensate the level decay of the tail, before entering the release period when the reverberation has decayed below the threshold and it then decays away naturally. You could combine that with some non-linear reflections for very interesting effects!

Bit Depth

Reverbs of old were often limited in their processing bit depth. That created a noisy, gritty atmosphere.

That effect can now be revisited in Illusion by setting a 10 or 12-bit resolution on the inputs and outputs, but you can have some fun by taking things to extremes as well by aggressively crushing the reflections and reverb itself which starts to exhibit very dirty gate-like effects.

The bit depth can be selected down to an excruciating 6-bit through to a near-transparent 18-bit, or of course disabled entirely.

The 5-band master equalisers for the early reflections and late reverb modules are placed after the crushers, so you can shape the effect of the bit-depth tools with roll-off or shelving filters very easily if you need to do so.

Brick Wall Filtering

Reverbs operating at low sample rates use sharp anti-aliasing filters within the audible frequency spectrum. This accounts for important part of the very characteristic tone of many early digital reverbs from the 1970s and 1980s. Dropping an 8 to 10 kHz brick-wall filter over a verb is excellent for creating a vintage atmosphere. Many of the presets take that further by reducing the reverb density to reproduce the sparse sound of early reverberators.

The brick-wall filter was already in use in Illusion before v1.2 and played a role in many of the vintage presets by introducing a sharp cut to the bandwidth of the reverb in a way that brings back memories of old devices with limited bandwidth like the original Lexicon 224 (which operated at 20 kHz, this means audio was limited to a maximum of 10 kHz although there is not much going on above 8 kHz). Pull up some of the vintage presets and you will see many with a cut-off around 8, 10 or 12 kHz. Many of you won’t have spotted the control hiding in the settings menu before so probably never played with it directly – now you can and there’s more resolution to the control too.

The brick wall filter can be set between 6 to 18 kHz, and has two modes. The ‘steep’ mode is a filter with a very fast roll-off but without the harsh corner frequency effects that the ‘sharp’ mode exhibits. I found a very sharp filter was sometimes a little too abrasive so provided two options here.


In Windows 11 a small graphical corruption was observed with the metering which has been corrected.

In macOS the use of OpenGL is now deprecated (Illusion did not use it in Windows). This technology will ultimately be removed by Apple, and on Apple Silicon systems it has been noted that performance when using OpenGL can be degraded significantly with more than one plug-in window open at a time. For this reason the default for new installations is to use the native macOS drawing APIs rather than OpenGL. When Apple finally retires OpenGL it will be removed from Illusion as well. If you wish to re-enable it then a new option is available in the settings menu to allow you to do this.


To get the update just install the full plug-in over the top of your existing installation.

Downloads: macOS | Windows

Important: Please ensure you have iLok License Manager v5.4 and up.

I hope you enjoy the new features in Illusion. Why not try out a demo today if you’ve not spent much time with Illusion before, or if you already own a license just pick up the installer here to update to the latest version for free.