Review – Some New Modular Expansions from Softube

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Softube does it again with four amazing new modules for their Modular system.  These are far more than just another oscillator, filter, VCA and reverb module.


by Warren Burt, Nov. 2017


Swedish “Rock’n’Roll Scientists” Softube released an amazing, and inexpensive, modular synthesis system last year.  Called Softube Modular, it contained excellent software emulations of a number of Doepfer modules, as well as their own slew of utility modules, and along with this, they released a trio of “Expansions,” emulations of modules by Intellijel, which brought some of the advanced features of the Eurorack format to the on-screen synthesis world.  I reviewed this very favorably back in July 2016 ( and noted that Softube said that new modules – emulations of interesting synthesis modules – were on the way, and that I was looking forward to them.

Fast forward to the present, a little over a year later, and boy, have they ever made good on their promise.  All of the new modules for the Modular system are excellent and have wonderful capabilities.  There’s the Buchla 259e Twisted Waveform Generator, an update on an old classic; the 4ms Spectral Multiband Resonator, which will have you rewriting your definitions of what a filter can be; the Doepfer A-101-2 Vactrol Low Pass Gate, another updating of an old favorite; and Softube has adapted their TSAR1 algorithmic reverb so that it works not only in the Modular environment, but also works as a VST or AAX plugin as well.

As I stated in my review last year, you need a mouse with a scroll wheel to navigate through the list of modules.  I didn’t have a scroll-wheel mouse connected when I first accessed the new modules and was puzzled how to navigate through more than a screen-full of modules that are at first displayed by the program.  When I plugged a scroll-wheel mouse into my computer, all was revealed.  This happened in both Reaper and Plogue Bidule, my two hosts for this test. 

There’s so much on offer here, it’s hard to know where to start, but just arbitrarily, let’s start with the 4ms Spectral Multiband Resonator.

The 4ms Spectral Multiband Resonator is a faithful emulation of the Eurorack module of the same name.  It consists of six parallel bandpass filters, each of which can act as standard bandpass filters, or with high enough Q settings, resonate at any desired frequency.  So it can be used as a set of tuned resonators as well as a set of bandpass filters.  But here’s where things get very interesting.  There are a number of preset “tunings” for the filters, each consisting of twenty pitches.  Some of these are microtonal, and others are in normal equal-temperament.  They are selected with the Bank knob at the upper right.  The assigning of the pitches to the particular filters, however, is controlled by the Rotate knob in the center, as well as the Scale knob at the upper right, the Morph knob in the lower right; and the Spread knob to the right of that.  The interaction between these controls can produce an amazing variety of “pitch-colored” filterings and ringings.  As well, each of the filters has an envelope follower on it, which can be used for controlling things with the envelope of the individual channel, either gliding, or quantized to the pitches of the chosen scale (depending on the setting of the 1V/Oct switch).  If you “ping” the inputs with a burst of noise with the Q set high, you can get various kinds of ringing notes and chords happening. An input such as a speaking voice will produce wonderful timbre-colors to mix with your voice.  If you make two instances of the filter, and patch them together in the right way, you can get vocoder effects happening.  And all these effects, of course, can be voltage controlled, so that continuous changing of the kinds of effects being obtained are possible.  I’ve been in love with the sounds produced by tunable filter-banks for many years, but this module is one of the most versatile and beautiful sounding filter-bank modules I’ve seen.  I’ve barely begun playing with it, and I can already see enormous potential in what it can do.  And the fact that it has a number of microtonal scales and resources built in to it certainly makes it even more attractive to me.  If this was the only Extension that Softube had brought out this year, I would be ecstatic.  But, as they say, wait, there’s more!

The Buchla 259e Twisted Waveform Generator was one of the most attractive and unusual modules in the Buchla 200-series synthesizer.  Softube has now gotten permission to emulate it in software, and the emulation is a thing of joy to behold.  One immediate point of interest is the slight changes that were made to adopt this module to the Softube environment.  You’ll notice the graphic of the faceplate has both normal “mini” jacks (the Eurorack standard), and the characteristic Buchla “banana” jacks for control functions.  In the interest of historical continuity, Softube has kept the graphics of this distinction, but in fact, any jack in the system will accept a signal from any other jack.  So the distinction, which Buchla maintains in hardware, between signal and CV, is maintained in the graphics, but not, in fact, in the actual functioning.  (And surely, back in the 70s, our Buchla studio at the University of California, San Diego, couldn’t have been the only Buchla studio with a good supply of home-brew banana-to-mini-jack patchcords!) 

The Twisted Waveform Generator is actually two oscillators in one module, and these oscillators can be set up into a standard frequency modulation (FM) patch.  But each oscillator can use two versions of eight different waveforms each, three of which are not standard waveforms, but bits of the actual programming code for the oscillator itself.  These can be scanned through at various rates, producing all sorts of glorious noises.  And these two versions of the eight basic waveforms can be morphed between, either manually or under voltage-control, as well.  There are a number of different kinds of morphing, and wave-table scanning (called warping here), and pitch modulation available, meaning that the waveform generator can go well beyond basic FM type sounds.  In fact, in terms of timbral flexibility, this “oscillator” is one of the most versatile sound generating modules you can own.  And, of course, since the module is virtual, and not physical, you can load up as many copies of the module as your CPU can stand. (The system is moderately CPU heavy, but on my i5 dual-core machine, I haven’t noticed any problems with overload yet.)  I set up a patch with five of the Twisted Waveform Generators in an “A modulates B modulates C modulates A” kind of feedback patch, and then sat back and adjusted a few knobs and listened to a gloriously complex noisescape of a kind that I hadn’t heard since I’d last worked with a Buchla system (and that was only a System 100!) back in the mid-70s.

A Vactrol is a device which consists of two parts – one is the input, where a changing voltage changes the brightness of an LED – and the other is the output, where the brightness of the LED is read by a photocell and turned back into a voltage.  This produces a kind of voltage change that is dependent on the characteristics of the photocell and the LED, introducing a kind of slight physical irregularity into the world of voltage-control.  Both the Buchla and Serge systems used Vactrols to control various aspects of their modules.  (I remember soldering Vactrols into Serge modules, but I can’t remember which ones – the New Timbral Oscillator? the Phaser? the Filter?)  In the case of the Buchla 200 series Low Pass Gate, the Vactrol was used to open the Amplifier and Low Pass Filter components of the module simultaneously.  This produced the kind of “more high harmonics with louder amplitude” behaviour that most acoustic instruments have, and this module can do just that – have a kind of linking of amplitude and filter control that emulates physical objects, most notably percussive sounds.  But not to be outdone, the module features emulations of three different Vactrols, selected with a switch in the lower right.  So you can have three slightly different characteristics to your Filter/Gate combination.  Additionally, you can select to have just the Low Pass function, or just the VCA function, or both.  And you can change these functions with two external signals.  The manual warns you that two “high” signals into inputs G1 and G2 is a “forbidden condition” and that “unpredictable behaviors” can result.  I haven’t tried that yet, but you can be sure that I’ll be doing that at an early opportunity.   The sound of the module is very clean, clear and precise.  It’s very reasonably priced, and everyone who has a Softube Modular system should have one.


Softube already had a superb algorithmic reverb with their TSAR reverb (the acronym stands for True Stereo Algorithmic Reverb), but now they’ve adapted it for use in Softube Modular.  Both the larger TSAR-1, with more controls over the parameters of the reverb algorithm, and the smaller TSAR-1R, with fewer controls, can now be used within the Modular environment.  Seeing as how Modular had no reverb modules in its early editions, the addition of a reverb to it is indeed welcome.  And what a good reverb it is.  The main word I would use to describe this reverb is SMOOOOTH.  Using the TSAR-1R, I changed the controls in real time, while processing sound through it, and never heard so much as a crackle or a sputter.  (Doing this with the TSAR-1 will produce some dropouts – because you’re changing aspects of the reverb signal, like density, which will result in silencing the sound with a decreasing number of reflections, for example.)  The 15 second setting in the TSAR-1R produces a lovely long lasting cloud of reflections.  I set up a monophonic patch controlling a triangle wave tuned in eleven-tone-per-octave equal temperament, played through the TSAR-1R with maximum 15 second reverb.  I then had a low frequency sine wave controlling the volume of the reverb output.  The result was lovely – a cloud of chords of overlapping 11 tone ET triangle waves, fading in and out.  This reverb unit can be used for far more than just setting up an ambience around your electronically generated tones.  I could go on praising its quality (and it’s well worth the price, since you can also use it as a VST or AAX plugin as well), but I’ll simply say that it’s a lovely piece of work, and if you do have Modular, I would say that having TSAR is a no-brainer, despite the price.  Reverb quality is like wine – everyone’s tastes are different.  But if you’re looking for a good algorithmic reverb, you should definitely include TSAR on your list of “trial-downloads” to compare with other reverbs.  You’ll probably like what you hear.

In short, Softube has amply fulfilled the promises of the first version of Modular.  These new modules expand what you can do with the program exponentially, and they offer lots of possibilities for control and sound exploration. If you already have Modular, getting these modules should be essential.  If you don’t have Modular, you now have four more reasons to want to have it.  I eagerly look forward to seeing what other Eurorack (and other) modules the good folks at Softube will make available.  I’ll probably be one of the first to get them.  And while we’re talking about the future, in my last review, I asked if it would be possible for Softube to develop a microtonal utility quantizer module, where any incoming MIDI or CV signal could be mapped to any user supplied microtonal scale (in .scl, .tun, or MTS format).  I’m asking once again about this – a module which I think would introduce a lot of pitch flexibility into the Modular environment.


Here now the details:

Mac OSX 10.9 or newer; Windows 64 bit only, Versions 7, 8 or 10.  Screen resolution larger than 1280×800; Softube/Gobbler account required; iLok account required.  Scroll-wheel mouse required on PC.

Buchla 259e Twisted Waveform Generator: $79 USD ($99 USD)

Doepfer A-101-2 Vactrol LPG: $29 USD ($39 USD)

TSAR-1 and TSAR1R Reverb: $149 USD ($249 USD)

4ms Spectral Multiband Resonator (SMR): $39 ($49 USD)

First prices are current sale prices, full retail is listed in parentheses after those.





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