Review – Softube Modular Software Synthesizer

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Swedish “Rock and Roll Scientists” Softube introduce the Eurorack format to the world of screen-based software synthesis with an outstanding collection of modules by Doepfer, Intellijel and others.


by Warren Burt, July 2016


In the world of hardware synthesis, the biggest news for the past decade has been the analog synthesizer resurgence.  Or maybe that should be the modular synthesizer resurgence, because a number of the newer “analog” modules are actually digital, but they have an interface of knobs, jacks and have certain parameters which are voltage controllable.  Among the new modular synths, the most popular format has been the Eurorack format, which uses jacks of a certain kind, module faceplates of a particular size, and a common power supply system to power the modules that you place together in your rack.  There are over 4000 Eurorack modules now available from over 150 manufacturers, and I’ve seen a number of systems that consist of a number of modules from different manufacturers happily living together in one cabinet.

Having been involved in modular synthesis since the late 60s, and having sold my rather large Serge and Driscoll synthesizer systems about five years ago, I’ve been watching the modular resurgence with mixed feelings.  On one hand, I’m envious of those who can afford to assemble collections of unique modules that have all sorts of unusual compositional potentials.  On the other hand, I realize that my lifestyle – tied to a commuter train – doesn’t permit me to go down that route, and I’m not sure I want to return to the days of wrangling patch cords again.  To be sure, I’ve been delighted with various modular synths on the computer screen – Arturia’s Modular V, and Martin Fay’s classic Vaz Modular have been favorites of mine for years, and in this issue of SoundBytes, I review the Moog Model 15 app in its iPhone incarnation.  So I haven’t been totally bereft of modular patching goodies in the past few years, even if they’ve all been screen based.  As an aside, a political note here – Martin Fay suspended sales of Vaz Modular at the beginning of 2015 to comply with UK/EU cross-border VAT regulations.  Now that Britain looks like it will be leaving the EU, I wonder if Martin will be able to start selling Vaz Modular again?

Dieter Doepfer, German synthesizer designer, is the guy who spearheaded the Eurorack synthesizer proliferation in the mid-1990s.  His modules have since become classics.  Now, in conjunction with the Swedish company Softube, he’s collaborated on the design of Softube Modular, a software emulation of a number of his classic modules, along with a very interesting and useful assortment of what Softube modestly calls “utility modules.”  The Eurorack format, it seems, has come to the computer screen, for both Windows and Mac computers.

A good friend of mine has quite a different point of view on these things. She looks at a screen with a copy of a physical machine, whether modular or not, and with a snicker and a snort, asks “Why would you want to do that?” I understand her scepticism. While being delighted to have either an emulation of an old favorite synth, or one that I could never afford, or even a new system that does things I couldn’t do before, the question remains – why would one want to hobble a universal system like a computer with a set of parameters and a method of operation that are limited by pre-existing equipment?  To do so reminds me of Canadian media theorist Marshall McLuhan’s idea that often, the first use of new technologies is to copy the functions of old ones.  However, it does seem that one of the models for music-making that evolved in the 1960s was the modular synthesizer, and this model not only worked in the world of hardware, it worked in the realm of software as well – think of older programs like CSound, or newer programs such as the Composers’ Desktop Project.  Both use the concept of separate function blocks (modules) connected in chains to make sounds, and this model has proved a fruitful one over the years.  So while I enjoy connecting a group of modules in a clever way to make a sound I haven’t heard before, I’m still aware of the limitations I’m placing on myself, and indeed, the basic absurdity of what I’m doing.  However, it’s an absurdity I can not only live with, but celebrate, and be creative with.

Which brings us to Softube’s new Modular, which is a collection of faithful modellings of six of Doepfer’s classic modules – the Voltage Controlled Oscillator, Voltage Controlled Filter, Voltage Controlled Amplifier, the ADSR Envelope Generator, a Low Frequency Oscillator, and a Noise Source.  These all seem to my ears to be very faithful reproductions of Doepfer’s originals, and have all the capabilities of the original modules.  These modules are then augmented by a set of 20 modules made by Softube, which provide many different basic composing functions found in most analog synthesizers.  Softube say that this is just the beginning of making available to the world of software synthesis some of the best and most creative modules from the Eurorack world.  As part of this, they have also made available three modules by Intellijel, an elegant FM oscillator, a very fancy filter, and a wavefolder module that is very useful.  These are available for separate purchase from the basic modular setup.  And if the asking price of some of these seems just a little bit high, remember that in this system, one can have as many copies of a module as one wishes.  (Up to the limit of 100 modules in a patch.)  And further, if one has Softube’s Rhythm synthesizer Heartbeat, the drum synthesis modules which form the core of that very useful machine show up as available sound generators in Modular as well.   Softube promises that further modules will be released in the future.  I, for one, will follow this development eagerly.  I’m very curious to see what new modules they will make available (for example, I’d be very interested in some of the sequencing and control modules from MakeNoise being made available!)

So how does it work?  When you first launch the plugin, you see a blank set of racks, with only a single bar in the middle.  Note the Inputs at the left.  This is because I’m here using the FX version of the plugin.  The presence of the external inputs is the only difference between the FX and normal versions.  Next to the inputs are some Module manipulation buttons, and then the Outputs.  An overall volume control, level meters and some auxiliary outputs are next, completed by some “Block DC on Aux Out” buttons, which go off screen to the right.  Navigation around the screen is accomplished by clicking and dragging with the mouse.  When you first start up the program, you have up to four rows of racks in which to insert modules.


Next, click on the “Modules: Add” button, and a screen of modules comes up.  You select from this screen by clicking on the module you want.  If you want more than one module, shift-click on the modules you want.  These are then deposited in the racks, starting at the upper left.  This view shows the full range of modules available. If there are modules that you haven’t purchased, such as the Intellijel or Heartbeat modules, they will be greyed out.  The categories are from top left, the Doepfer module emulations, the Intellijel modules, DAW and MIDI interfacing modules, Effects (a small category at the moment, which Softube says will expand very soon), Heartbeat sound generating (percussion sound) modules, Mixers, Sequencers, Utility and Performance modules.


Next you select the modules you want.  Here, I selected a standard “synth channel’s” worth of modules: a MIDI to CV, an Oscillator, a Filter, an Intellijel uFold, a VCA, an ADSR, and an Audio Mixer. I then proceed to connect these modules together with virtual patch cords, by clicking on an output jack and dragging that to an input.  After I click on the output jack, possible inputs are highlighted in green.  Once the jacks are connected, the patch cords disappear, but the jacks are highlighted in the same color.  If you want to see the patch cord again, just hold your mouse on either the input or output jack and it will appear, with the other patch cords appearing with translucent color.  Here, I’ve patched the modules to make a standard synth voice, with the exception that after the VCA, I’ve patched the sound through the uFold, in order to introduce some waveshaping onto the sound.  If I want to move or delete a module, I just click on the “Module: Move/Delete” button.  To move a module, click on it, then click in the place you’d like to move it to.  To delete, just click on the “X” button at the upper right that appears when in this mode.  In this shot, I’m holding my mouse on the output of a patch cord so that you can see it.


I now add two Dividers to the patch, along with a Noise Source, two Sample and Holds, and a Low Frequency Oscillator.  The external sound comes from the sound Input jacks into the Dividers, and the division ratio of each Divider is controlled by a separate random voltage coming from the Noise Source through the Sample and Holds, which are triggered off by the Square Wave output of the LFO.  This signal is very noisy and very distorted, and is in stereo, so each signal goes to a different Audio Mix, which each go to a separate Output.


Now for something completely different.  In this patch, I’ve connected three of the Intellijel uFolds in series, and then routed the output of that through the Intellijel Korgasmatron II, a very clean and versatile filter module.  The output of the filter goes back into the series of uFolds, creating a feedback loop. I then take one of the Performance modules, this one with four knobs, and by clicking on the “Perform/Edit” button, have programmed it to control the Folds controls of the three uFold modules, and the Cutoff of the filter module.  The knobs being controlled are colored red, so you can see what controls you’ve selected to control in this manner.  By adjusting the four controls, now conveniently in one panel, you can sculpt your squealing noisy feedback path into something that might amuse you and your noisecore friends for hours on end.


For those of you who would like to apply external automation to a patch like this, or use a program such as Max/MSP, PD, or MusicWonk to make a whole swathe of external MIDI continuous controller signals to control the knobs on the screen, be assured you can do this.  Just route your continuous controllers from your MIDI program of choice into the automation selection routine of your DAW (I’m using Plogue Bidule, which allows very easy routing of any incoming MIDI signal to any target in any plugin), and you have external automated control of any on-screen control in Modular. 

For those of you who like old-fashioned step sequencers, there are three of these in Modular, along with an x0x-style Beat Sequencer.  Since you can have as many of these as your racks can hold, the possibilitiy for very complex sequencing controls is very great.

The Intellijel modules deserve a mention all of their own – they’re elegant and very powerful.  The Rubicon is a very clean and beautiful sounding FM oscillator – it has normal exponential FM, as well as Through-Zero FM, which produces really sparkling spectra, and a raft of useful controls.  As mentioned above, the Korasmotron II is a dual filter in which many interesting interactions with the filters can be made, and it has a feedback loop which can be taken out and routed through other modules, making some very unique filter sounds.  The uFold is a very elegant waveshaping module, which produces some very attractive timbres.  All three are highly recommended as additions to the basic Modular kit.  And for those of you into synthetic percussion, the Drum synth modules in Heartbeat, which then become available in Modular, offer some very nice and controllable percussion timbres.  I was pleasantly surprised at hearing the range of very attractive timbres they produced. 

In short, if you want to explore the world of analog modular patching synthesis, Softube Modular is definitely something you should consider.  And remember, Softube has said that this is only the beginning of this project, as they hope to be able to release emulations of many other Eurorack modules in the future.  So in getting this software, you’re embarking on what will hopefully be an open ended project that will keep expanding as the years go by.  Are there any things I would like to see in future editions of the program?  Just two – it would be nice if you could have a check-box that would turn on numerical tool-tips for the knob you’re currently turning.  The joy of analog modular synthesis was that you had to do it all “by ear,” listening to the sound results as you turned the knob until you got what you wanted.  That’s a very good way of working, but for certain things (like fine tuning) sometimes you want a numerical output in order to be sure of what you’re getting.  Another module I’d really like to see is a “tuning quantizer” module, where you could quantize the output of any CV processor into any microtonal scale you wanted.  You would do this by loading a Scala standard .scl, .tun, or .MTS file into the module.  This was one of the most useful modules in Vaz Modular for me, and I think the addition of it to the “Utility” section of Softube Modular would give the synth a power that it currently doesn’t have.  Aside from those two wishes, I think that this software is just about perfect, its operation is ultra-smooth, it sounds great, and I wouldn’t hesitate recommending it to anyone.


VST, VST3, Audio Units and AAX Native Formats – Windows and Mac, 64 and 32-bit versions available; iLok required. 

Softube Modular $99 USD; Intellijel Rubicon $49 USD; Intellijel Korgasmatron $49 USD; Intellijel uFold II $29 USD; Softube Heartbeat Drum Synthesizer $169 USD. 

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