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SSL FlexVerb Plug-in - User Guide


FlexVerb is a fully-featured SSL reverb plug-in designed to get a professional mix-ready sound in a quick and intuitive way. Its split early-late reflection architecture allows you to flexibly add the body and tone of different early room reflections, complimented by the richness of a variety of expansive reverb tail options. Complete with 6-band EQ and input side-chain compressor, FlexVerb is easy to use and an extremely powerful creative tool for the audio professional. 


Key Features:

  • Four Reverb Types: Room, Hall, Plate, and Chamber. 
  • Early & Late Reflection types can be independently selected; for example, Small Room Early Reflections, with a Large Plate Reverb Tail. 
  • 6 Band SSL EQ, with 3 bands of reverb time multipliers. 
  • Output compressor (applied to reverb only) side-chained by the ‘dry’ input signal; useful to help sit in the mix. 
  • Lockable Dry/Wet Mix control; fix the mix of dry and wet signal when switching between presets. 
  • Infinity reverb time switch. 
  • Reverb tail kill switch. 
  • Graphical display of EQ and reverb time multipliers, including FFT analysis with after-glow.


Release Notes


  • New features
    • Native support for Apple silicon (VST, VST3 and AU only).
  • Bugfixes and improvements
    • Updated to the new SSL Plug-in Engine framework.

V6.5.X (SSL Native V6.5)

  • New features
    • Uninstaller applications for macOS and Windows.
  • Bugfixes
    • Rewrote FlexVerb parameter change response, fixing several minor bugs.
    • Fixed inconsistent behaviour of displays when bypassing plug-ins.



We recommend using the SSL Download Manager application to to easily manage all SSL plug-in installations all from one place, on both macOS and Windows. In addition to easily installing, uninstalling or reinstalling individual or every SSL plug-in at the click of a button, the SSL Download Manager also provides you with detailed release notes and lets you know when updates are available.

You can also download offline installers for a plug-in from here.

All SSL plug-ins are supplied in VST, VST3, AU (macOS only) and AAX (Pro Tools) formats.

The installers provided (macOS Intel .dmg and Windows .exe) copy the plug-in binaries to the common VST, VST3, AU and AAX directories. After this, the host DAW should recognise the plug-in automatically in most cases. Simply run the installer and you should be good to go. You can find more information about how to authorise your plug-ins below.


Visit iLok, Licensing and Activation for guidance in activating your SSL plug-in.

Using SSL Native FlexVerb


The illustration below gives an overview of the FlexVerb features which are described in full over the following pages. 


Interface Overview

The basic interface techniques for the FlexVerb are largely identical to those for the Channel Strip.

Plug-in Bypass


The power switch located above the Input section provides an internal plug-in bypass. This allows for smoother In/Out comparisons by avoiding the latency issues associated with the host application’s Bypass function. The button must be ‘lit’ for the plug-in to be in circuit.


Automation support for FlexVerb is the same as for the Channel Strip.


Factory presets are included in the plug-in installation, installed in the following locations:

Mac: Library/Application Support/Solid State Logic/SSLNative/Presets/FlexVerb

Windows 64-bit: C:\ProgramData\Solid State Logic\SSL Native\Presets\FlexVerb


Switching between presets can be achieved by clicking the left/right arrows in the preset management section of the plug-in GUI, and by clicking on the preset name which will open the preset management display.

Preset Management Display


There are a number of options in the Preset Management Display:

  • Load allows loading of presets not stored in the locations described above.
  • Save As... allows for storage of user presets.
  • Save as Default assigns the current plug-in settings to the Default Preset.
  • Copy A to B and Copy B to A assigns the plug-in settings of one comparison setting to the other.

A-B Comparisons


The A B buttons at the base of the screen allows you to load two independent settings and compare them quickly. When the plug-in is opened, setting A is selected by default. Clicking the A or B button will switch between setting A and setting B.

UNDO and REDO functions allow undo and redo of changes made to the plug-in parameters.

Input and Output Levels 

The input and output sections provide input and output gain control, and input/output metering. When clipping occurs, the meter will turn red. It will remain red until the meter is reset by clicking on the meter. 

FlexVerb Signal Flow 


Early Reflections and Reverb Tail Selection 

There are four reverb types: Room, Hall, Plate and Chamber. Each reverb type has three sizes: Small, Medium, and Large. 


Select the Early Reflection and Reverb Tail type and size by clicking on the drop-down selection boxes. 

With the LINK engaged, selecting the Early Reflection Type and Size will allocate the same settings for the Reverb Tail. With the LINK disengaged, the Reverb Tail Type and Size is independent of the Early Reflections. 

The INFINITE switch sets an infinite reverb time value, the KILL switch kills the reverb tail. 

Reverb Tail Control Section 

This section describes the functionality of the control faders for adjusting the reverb tail settings. 


3-Band Reverb Time Multipliers 

The reverb tail is split into three frequency bands with adjustable crossover points. Each of these frequency bands has an adjustable reverb time; the multipliers increase or decrease the reverb time parameter in the Reverb Tail control section (detailed above) for each frequency band. This is a useful way to shape the tonal quality of the reverb, and gives a more natural sound than using EQ. 


6-Band EQ 

Six bands of EQ can be applied to the reverb tail to shape overall reverb tone. This includes two parametric bands, high-shelf and low shelf bands, as well as high-pass and low-pass filters. The EQ only affects the reverb; it does not affect the input source signal.


Input Side-Chain Compressor 

A compressor is applied to the output of the reverb with nine presets (fixed attack, release, and ratio settings), and adjustable threshold control. The compressor's side-chain is fed by the dry input signal. 


This is useful, for example, to sit a larger-than-life vocal reverb in a busy mix; when there are vocals in the track, the accompanying reverb is automatically reduced in volume until the vocals stop, allowing the reverb to increase in level, giving the impression of a larger-than-life reverb without masking the intelligibility of the vocals. 

Graphical Display 

The graphical display shows: 

  • The resultant curve of the EQ section that can be adjusted from the draggable circular nodes. 
  • The reverb time multiplier crossover points and values that can be adjusted from the draggable square nodes. 
  • An FFT analysis with after-glow. 


The FFT can be switched off by right/CTRL-clicking the graphical display, and selecting 'off'. 


A Dry/Wet control for applying reverb directly to channel processing, rather than via an aux send. 


The lock function excludes the mix control parameter from the preset management system. 

The lock function is useful, for example, when switching between multiple presets; set the mix control to the preferred blend of 'Dry' input signal and 'Wet' reverb signal, then audition different reverb presets without affecting the mix.