If you want flexibility in synthesis with the opportunity to create complex sound designs, check out these top 10 modular synth plugins you can find in 2021.
Synthesizers are a staple in music production; there’s barely any modern song without some form of synthesized sound. Synths range from a simple 2-oscillator monophonic analog synth to advanced wavetable or granular synths. However, besides the oscillation engine, a synth also features filters, modulators, effect processors, etc.
That’s where the synth environment comes in. Some synths have a fixed chain of processors, while some provide some degree of control. The only way to achieve complete control, though, is by separating each step of processing into “modules.”
What Is Modular Synthesis?
Modular Synthesis is the system of synthesis where you connect individual modules of oscillators, filters, effects, modulators, utilities, etc., to create a unique synth setup. This technique lets you have complete control over the synth’s signal chain and achieve as complex a setup as you want.
How Does A Modular Synth Work?
Modular synths work by connecting compatible modules together. For example, in hardware, you could use a Korg oscillator with a Behringer Filter and a BOSS distortion. Similarly, most software versions come with a package of a large variety of modules or offer separate purchases to build your unique synth.
The most sought-for feature of a modular synth is its endless possibility of sound design. You could use complex filter chains, feedbacks, or parallel processing to achieve sounds impossible to reproduce via traditional synthesis. And while having hardware is probably the most fun way to explore modular synthesis, there are some unique advantages to having software plugins.
The biggest plus for software is that it’s much cheaper than hardware. However, other than that, you can experiment more with software. You have to restrict yourself to “safer” signal chains in hardware, whereas, for example, uncontrolled feedback would result in a crash at the most with software. Similarly, some software synths let you create parallel chains with way more channels than their hardware counterparts have.
And with that in mind, let’s have a look at our list of the best modular synths in 2021.
Top 10 Modular Synth Plugins 2021
1. Sugar Bytes Factory
Factory is the fastest way to create intricate, evolving sounds with a meager amount of effort.
At its core, Factory has two oscillators, eight kinds of modulators, and three effects. However, the plugin takes everything above and beyond what we usually see. You can modulate just about every parameter using two LFOs, two envelopes, and four sequencers.
Furthermore, Factory has a dedicated modulation matrix, which users of Image-Line Sytrus should immediately recognize. On the left of the matrix, you’ll find the modulation sources like the LFO, envelope, etc. And at the bottom, you’ll find the modulation targets. We’ll talk more about this below.
- The Matrix
There are eight modulation sources and ten target slots. However, you can switch any of the slots for another. For example, suppose you used LFO 2 to modulate several parameters. Then, you realize you’d rather use Sequencer 1 instead. All you have to do is switch the LFO 2 slot for Sequencer 1!
In the Matrix, blue blobs show a positive value, whereas the pink ones indicate a negative value. Also, a value indicator at the top of the interface shows you precise percentages of your modulation, so you needn’t rely on the blob size alone.
Factory has two truly incredible oscillators. Each features ten modes, including subtractive waves, wavetable modes, waveguide, FM, and transformer. Here, the transformer mode lets you use audio samples as oscillators. Unfortunately, there is no visual representation of the waveforms in the wavetable modes.
Under the Modulator tab, you will find two envelopes and two LFOs. While they are pretty standard, both employ a shape knob that lets you create funky shapes out of your envelopes and LFOs. The envelopes get exponential shapes in various parts of their curves. Similarly, the LFOs dance around with different shapes, from the typical sinewave and saw-wave to asymmetric and randomized waves.
Factory’s sequencers are probably the most potent modulators of all. I wasn’t expecting much when experimenting with it, but then I opened its step shapes. Each step in the sequencer can have a unique shape, from a simple square or curved fade-in shape to insane curves that I can only describe as anime hair. You’ll find 36 step shapes.
Under the Effects tab, you’ll find three effect slots, where you can load from an array of effect processors and change the order of the slots. There are 17 effects in total, including delays, reverbs, EQ, filters, chorus, phaser, compressors, Lo-Fi, etc. Other than such effects, you’ll find features like arpeggiator, glide, scale quantization, intonation, and so on under the Arpiculation tab.
You can morph between two presets or variations of the same preset using the Morph slider. It’s handy for creating changes between two parts of a song, for example. Similarly, the modulation matrix features a knob that lets you control the value of each modulator at the same time, proportionately. You can automate both parameters to achieve complex results quickly.
The plugin is available for Windows 7 or higher and macOS 10.9 or higher, both 64-bit only. It comes in VST 2, AU, and AAX formats.
In terms of features, Factory is chock-full of them. Thanks to the innovative step shapes, the oscillators are powerful, and the sequencers are second to none. Furthermore, the preset library features a characteristic-based search, making navigating the large preset bank much more effortless. However, I found Factory’s sound leaning towards a harsher sound. It works perfectly for EDM, hip-hop, electronica, and experimental music. But I wouldn’t recommend it to create pads for ambient or similar genres.
2. AAS Multiphonics CV-1
Featuring a real modular approach to the interface, this plugin is a playground for sonic creativity.
Multiphonics CV-1 is a gigantic library of modules ranging from filters and oscillators to handy effect processors. The interface and workflow are similar to using a hardware modular synth. So, you do need to know the basics of modular synthesis (like connecting the midi signals into the gate of the oscillators/other modules) to get started. However, there are plenty of online guides to help you out.
On the interface, you’ll find a workspace on the right and a list of modules available for you on the left. You can double-click a module on the list to insert it into the workspace, and you can also add duplicates of the same module. Furthermore, you can rearrange the modules to declutter your setup.
Multiphonics CV-1 contains 35 modules in total. I must mention that some of them, like the Keyboard, Master Clock, Macros, Output, or Patch Info, aren’t for sound design. So, excluding them, you will still have over 25 modules for pure sonic exploration. You’ll find an FM-capable oscillator module (and its younger sibling) capable of producing sine, triangle, saw, and square waves. Another generator is the noise module with adjustable noise density.
For CV (control voltage) modulation, you have a gate sequencer, an envelope, and an LFO. A fantastic feature here is that each produces multiple kinds of signals. For example, the envelope can create both positive and negative envelopes at the same time. Similarly, the LFO produces square, triangle, and sine waves simultaneously. So, you can “wire” them to multiple parameters without requiring numerous modules. Also, here’s a tip: you can also use the main oscillator as a source of CV modulation.
There are two filters in this plugin: State Variable Filter and Objeq Filter. State Variable Filter is the typical filter that features a band-pass, high-pass, and low-pass output, all of which you can use simultaneously for creative results. Similarly, the Objeq Filter is also a filter, which uses physical modeling. You can model a rectangular membrane, drumhead, rigid plate, string, marimba, and beam. It originates from the AAS Objeq Delay plugin and makes for an exciting sound design tool.
Other than filters, you will also find effect modules: a delay, dual delay, limiter, inverter, and a slew limiter. Furthermore, several other modules are useful for syncing sequences and general utility. Of course, learning to incorporate them all in your sound design will take time, but the freedom makes Multiphonics CV-1 an outstanding synthesizer.
The plugin is available for Windows 10 or higher and macOS 10.11 or higher, both 64-bit only. It comes in VST 2/3, AU, and AAX formats.
Multiphonics CV-1 is one of the best entries into the modular world that is unbelievably open and capable. The interface isn’t overly complicated, but neither is it nerfed; documentation and video tutorials help you get over the learning curve fast. Furthermore, the included presets organized into fifteen categories are abundant, genuinely useful, and help get you started. Overall, the sound, workflow, and efficiency are all excellent, and I highly recommend the synth.
3. Native Instruments Reaktor 6
Take complete control of your sound using one of the best synths made by Native Instruments yet.
Reaktor 6 is a powerful modular synth that uses “blocks” or modules to allow advanced sound design. However, instead of merely providing you with proprietary modules, Reaktor 6 enables third-party developers to contribute to the modular synth, making it an ever-expanding instrument.
If you have used a modular hardware setup, you’ll notice that Reaktor 6 resembles the workflow closely. Native Instruments provides a Blocks Base version, which is free, and the paid version. The Blocks Base version features 24 blocks that let you explore an impressive level of sound production. Conversely, the paid version adds 26 more modules (Primes) with NI’s acclaimed synth technology for complete sound design freedom. Let’s talk more about the latter.
As I’ve mentioned, there are a total of 50 blocks or modules in Reaktor 6. These include oscillators, filters, modulators, sequencers, effects processors, etc. In other words, you’ll find everything you’ll need for sound generation, mixing, and modulating. I also like how versatile Reaktor 6 is; it can create both soft and heavenly or ear-rattling and harsh sounds. Furthermore, you can even use feedback looping in your sound design, which is often only found in hardware.
- Included Instruments
While Reaktor 6 is a modular synth, it also features over 80 pre-programmed instruments that function like regular synths. These include instruments like Gauger Ensemble, Photone Ensemble, Space Master, Skrewell, Newscool, Lazerbass, etc. Furthermore, you can edit and customize these instruments any way you like.
- Beyond The Face
As impressive as Reaktor’s modular synthesis is, there’s much more it can do. Reaktor 6 features two structural levels called Primary and Core. Primary is the modular synth part, where you can create sounds using a hardware-like approach. Each part you use here is either called Primary Macros or Modules.
The second level, Core, is the deepest level. Here, you can access machine coding to modify macros or create new DSP algorithms essentially. Furthermore, Reaktor 6 provides you with a comprehensive library of DSP components.
Reaktor 6 supports 3rd party developers to expand their already vast library with more blocks and instruments. As of now, you’ll find over 200 partner modules from developers like Toybox, Euro Reakt, GENKI Instruments, etc. Similarly, you’ll also find a range of third-party instruments from companies like Heavyocity, Blinksonic, etc. Often, these instruments are made for the free Reaktor Player too.
The plugin is available for Windows 10 or higher and macOS 10.14 or higher, both 64-bit only. It comes in VST 2/3, AU, and AAX formats.
Reaktor 6 is enormous. It has far too many features and depth to summarize in a short text. Hence, I suggest checking out the free Reaktor 6 Player to find out what it can offer you. Reaktor 6 is highly efficient at producing just about any kind of sound, from dub-step growls to cinematic atmospheres and gentle arpeggios. And if you aren’t familiar with modular synthesis yet, the instruments included with the library let you utilize the sound of Reaktor 6 before you have mastered the synth itself.
Speaking of which, Reaktor 6 includes 19 preset factory patches that feature simple subtractive synths to experimental laboratories. You can either use these alone or incorporate them in your sound design to expand your ideas even more.
4. Cherry Audio PS-20
Breathe life into the renowned classic Korg MS-20 with this tribute by Cherry Audio.
PS-20 is a highly accurate recreation of the hardware but with many a twist and quirk. For example, it features 16-note polyphony over the monophonic original. PS-20 has a very unique and vintage-like sound you might love if you are into analog synthesizers.
- Oscillator Modules
PS-20 features two nearly-identical oscillator modules. Both of them can generate triangle, saw, and square waves (with PWM). However, the first one features a sub-oscillator as well. Similarly, the second oscillator can employ ring modulation with the first oscillator.
The filter module has a high-pass and a low-pass filter. PS-20’s filters accurately emulate the original MS-20’s sound. You’ll notice the signature fat, distorted sound immediately. The Drive knob on the filters accentuates the saturation.
PS-20 employs an LFO generator and two envelopes. You’ll find saw and square (with PWM) waveforms in the LFO generator, and you can also assign the modulation wheel (CC 1) to control the LFO. Similarly, you can use velocity to control the envelopes.
As with the original hardware, PS-20 supports modular functions via virtual cables. However, Cherry Audio has changed the hardware’s obscure terminology into modern, standard terminologies, which should help make the workflow easier. Similarly, you can assign colors to the cables.
The plugin is available for Windows 7 or higher and macOS 10.9.5 or higher, both 64-bit only. It comes in VST 2/3, AU, and AAX formats.
PS-20 successfully recreates the raunchy sound of the Korg MS-20 using deep software emulation. Furthermore, its 16 polyphony makes it an analog enthusiast’s dream come true. And the price is fair too. While you probably won’t find much use for this plugin for creating evolving pads or atmospheres, it’s spot-on for dirty basses and leads.
5. Arturia Modular V3
Arturia takes us back to the roots of synthesis with this emulation of a revered classic.
The Arturia Modular V is based on the Moog Model 55 modular synth, which was a two-notes polyphonic synth. This software emulation adds sensible features like formant filtering and 64-voice polyphony to the original design. The interface, however, remains faithful to the hardware along with the manual patching workflow.
- Powerful Oscillators
Sometimes, more is more in synthesis. Modular V features 9 oscillators in total, and each can generate sine, triangle, saw, and square waves. Furthermore, they also feature frequency and amplitude modulations. While it may seem unnecessary to have so many oscillators, you’ll probably spend most of them for unison as there isn’t a dedicated feature for that. Also, there’s a noise generator.
- Moog Filters
There are three filter modules in the plugin, and they accurately recreate the sound of the original filters (low-pass). The plugin lets you select one of four types of filters for each module: a low-pass, high-pass, notch, and a band-pass, all of them with 24 dB/octave slope steepness. Furthermore, you’ll also find a Fixed Filter Bank, where you can equalize the signal coming from the two output amplifiers (VCA) using 14 bands.
- Effect Processors
The plugin features chorus, phaser, and stereo delay processors. There are three chorus types selectable with a toggle switch. And you can sync the stereo delay to the host tempo. You’ll probably want to use the delay as an echo effect rather than as a spatial effect.
- Sequence Generator
This module, better known as a sequencer, is comparable to the original model 960 sequencer but simplifies programming with internal connections. The low-frequency oscillator, the 8-step sequence manager, and the output controller are the three components of this module. The oscillator sets the playback rate, which can also be synced to the host.
The plugin is available for Windows 7 or higher and macOS 10.11 or higher, both 64-bit only. It comes in VST 2/3, AU, and AAX formats.
Featuring over 600 presets, Arturia’s Modular V is probably one of the most inspiring synths yet. However, the interface often feels overly large and clunky, especially if you use a smaller screen like a laptop, although it retains the original hardware’s feel. Sound-wise, the emulation is spot-on, and if you like analog sounds, this synth should be at a high place on your list.
6. Softube Modular
Are you looking for a premium environment for modular synthesis at a reasonable cost? Read on.
Softube Modular is a very expansive modular synth plugin. It features officially licensed, branded modules from top hardware manufacturers. Doepfer modules are included in the base package, with Buchla, Intellijel, 4ms, Doepfer, and Mutable Instruments as premium add-ons. The system feels like a proper hardware modular synth setup.
The base package also includes 50 stock modules by Softube, including mixers, sequencers, filters, etc. Furthermore, the plugin features over 400 presets, making it a welcoming experience for beginners and Eurorack masters alike.
- Not Just An Instrument
Surprisingly, Softube Modular also comes with a Modular FX version, which lets you use the intuitive modular system to process your DAW tracks too. You can build unique effect chains featuring compressors, chorus, doubler, distortion, etc., with complex filter routings all in a single plugin instance.
- Integration and Expansion
You can use many of the Softube effect plugins inside Modular as modules. Furthermore, I’ve already mentioned the add-on modules, which are released and expanded regularly. And thanks to Softube’s detailed component-based modeling, each add-on brings a unique flavor to your setup without sounding awkward.
- The Base Package
The Base package includes seven Doepfer modules: A-110-1 VCO, A-108 VCF, A-132-3 Dual VCA, A-140 ADSR, A-118 Noise/Random, A-147 VCLFO, and A-114 Ring Modulator. Furthermore, you’ll also find 50 additional stock modules, including utilities like midi-to-CV/gate, slew, sample & hold, sequencers, and DAW sync. Interestingly, you’ll also find a ROLI Seaboard RISE interface module, which can be handy if you own a ROLI Seaboard.
The plugin is available for Windows 10 or higher and macOS 10.13 or higher, both 64-bit only. It comes in VST 2/3, AU, and AAX formats.
Softube is a reliable manufacturer of quality plugins, and Modular’s integration with their plugins makes the sonic possibilities near limitless. Furthermore, it’s one of the few modular synth plugins with add-ons. Note that the Base package is undoubtedly feature-packed and capable of almost any kind of sound design. So, the add-ons are merely for tonal changes and variations.
7. u-he ACE
This plugin prioritizes the analog sound and provides a genuine hardware-like workflow.
ACE is an abbreviation for Any Cable Everywhere, and it stands up to its name. It’s a compact synth plugin that can be both simple and complex. It has up to 16-voice polyphony and a fully resizable UI. Furthermore, there are over 920 factory presets, making it an outstanding choice for beginners. However, note that it’s not the most straightforward synth to use, although the manual makes it a breeze.
- Analog Sound
There are two oscillators modeled on analog hardware in the plugin. They produce saw and pulse waves with PWM, sync, internal ring and cross/frequency modulation. One of them can also generate a sub-oscillator. Further, you can add up to 8-voice unison with ±2 octave individual detuning. At the bottom left, you’ll also find white and pink noise generators. Next, let’s talk about the filters. ACE employs two analog-style filters that support overdrive as well as self-oscillation.
ACE employs two envelopes and two LFOs. However, it also features a Mapping Generator on the Tweak page, which lets you draw shapes/patterns. You can use the shape for per-note modulation, step modulation, transform any modulation source, or even as the LFO 2 waveform. The generator syncs to the host to boot.
- Modular Nature
ACE is technically a semi-modular synth because of its fixed architecture. So, you can play it even without patching the cables. However, you can override the default routing by starting to patch. And as with hardware, you can use the signals from an LFO as an audio source and vice versa.
The plugin only features a few global effect processors: a chorus with four modes, a stereo delay, and a treble and bass control. The delay can be synced to the host without any patching.
The plugin is available for Windows 7 or higher 32-bit or 64-bit, macOS 10.9 or higher 64-bit, and Linux. It comes in VST 2/3, AU, and AAX formats.
ACE appears to be geared towards beginners, but it still might be too complicated out of the box. Experimenting with the cables is highly rewarding, but you do need to know what you are doing. That’s when the oscilloscope visualizer at the top of the interface comes in handy. Furthermore, the portamento features multiple glide options, which I found super useful for basslines. Overall, thanks to its large number of presets and the detailed manual, I think it’s a worthy investment for beginners, who can use the presets while learning this evergreen instrument. As a final note, though, ACE can be very CPU intensive because of its analog models.
8. Tracktion Hyperion
Hyperion has been dubbed an instant source of sonic inspiration for music producers, and it’s clear to see why.
Inspired by 80s legends like Vangelis, Jean-Michel Jarre, and Brian Eno, Hyperion strives to become the most flexible digital synth yet. It features multiple layers or “tracks” of patches to create complex sounds. Furthermore, you can save such multi-layer patches as combi patches too.
Hyperion also models analog warmth to make it even more appealing. It includes a lot of surgical controls and data generating modules. And finally, you can use the included effect processors to mix inside the plugin.
- Layers and Depth
As I’ve mentioned, Hyperion features up to 10 layers or tracks. Each can have a unique patch, including chord, arpeggiation, and bus effects. Similarly, each layer has in-depth control over various parameters like the pitch bend range, polyphony, portamento speed, etc., all of which work together to form intricate sound designs from a single plugin instance.
The oscillators in Hyperion are nothing sort of amazing. There are 9 types of oscillators: OSC (mono/stereo), wave sequence, 4-operator FM, FM wave sequence, plucked string, sample player, sound font, and flute physical model. To me, the scale of this plugin feels on par with something like UVI Falcon 2.
- Layer Processing
Each layer features multiple filter types, including low/high/band/notch with cutoff and resonance, slope/depth, stereo offset, and saturation control. Furthermore, you can also add effect processors like distortion, tube resonator, ring modulator, and bit crusher.
- Buss Effects
In addition to layer processing, you are also provided with reverb, chorus, flanger, tremolo, filters, distortion, 3-band EQ, delay, granulator, pitch shifter, etc. You can add them to buses and control bus sends per layer.
The plugin is available for Windows 8 or higher and macOS 10.11 or higher, both 64-bit only. It comes in VST 3 and AU formats.
In conclusion, I think Hyperion is an outstanding playground for sonic exploration. It’s a vast plugin with hundreds of presets and possibilities. If you enjoy having creative freedom to the fullest, you should check out this underrated diamond by Tracktion. Also, the pricing is fair for the quality you receive.
9. Unfiltered Audio Lion
With their breakthrough debut synthesizer, Unfiltered Audio is aiming for new heights.
Lion is a dual-oscillator synth with multiple modes per oscillator that range from traditional to unique waves. Furthermore, Lion’s mixer has a variety of settings for mixing the two oscillators in ways that no other synthesizer does. And once you’re done with those parts, you can explore new sounds using an array of high-quality effect processors.
- Oscillator Modes
Many synths have two oscillators, but few have as many as 26 modes per oscillator! You’ll find familiar subtractive and addictive waveforms to FM, super oscillator stacks, microsound, noise, and further variations. Furthermore, activate stereo mode on each oscillator even wider. These features are excellent for EDM.
- Effect Processors
Find over 40 effects that support modulation in Lion. You’ll find standard effects like reverb, delay, EQ, chorus, phaser, distortion, etc., and many more unique ones. Combining the effect processors with modulation sources like velocity and note tracking can create highly dynamic sounds.
There are over 600 presets in Lion that show the extent of the plugin’s efficiency. Furthermore, the randomization engine makes it even easier to create variations from presets to make your song sound as unique as ever.
The plugin is available for Windows 7 or higher and macOS 10.11 or higher, both 64-bit only. It comes in VST 2/3, AU, and AAX formats.
If you have used Unfiltered Audio plugins before, then you’re no stranger to their efficiency. And Lion reflects the legacy well. The plugin features everything you’d need to create sounds that barely even need any more processing out of the box. Features like per-voice modulation, unique mixing algorithms, and a single-page UI makes Lion a futuristic synth.
10. u-he Zebra (Wireless Modular)
Zebra2 is the definition of quality – whether it’s an intricate pad or a simple lead, it sounds like a true instrument.
This masterpiece by u-he is far more than a modular synth. It’s a laboratory for sonic discovery. You can combine freehand wavetables with FM synthesis or route traditional sounds through complicated comb filters to redefine sound designing. Despite being so complicated, though, Zebra2 manages to make the interface comprehensive.
Zebra2 features many modules that you can add to your patch. And in the center, you will find a matrix, where you can route each module to four stereo channels. You’ll find the modules you’ve added on either side of the matrix, and below them, you will find various other pages.
Zebra2 employs 4 wavetable oscillators that support drawing wavetables freehand and using spectral shaping for additive synthesis. You also get a large, flexible editor to draw your wavetables. Furthermore, there are 4 FM oscillators featuring eight waveforms rather than the traditional sine wave. You’ll find quadric sine, dual AM sine, half-sine, sine shift, etc.
Each main oscillator also features various parameters, including general ones like the tune, detune, unison (up to 11x), etc. However, the OSC effects are the most fun – you’ll find various processors that work on the oscillator to make it sound brighter, darker, or even cause complete turmoil. There are over 25 OSC FX.
Zebra2 has 4 regular filter modules with 23 modes and 4 cross-modulation filters (XMF) with 15 modes. Most of the regular filter modes sound very smooth and analog-like, and the module has a dedicated drive knob. However, the XMF modules are incredible. You can use two filters simultaneously in various modes, add distortion, and use FM via its extra input. There are five modes of distortion: XMF, Analogue, Biased, Eco, Folded. Here, the Biased mode emulates diode-based distortion, and the Folded mode introduces a Lo-Fi sound.
Zebra2 features 4 envelopes, 4 multi-stage envelopes generators (MSEG), 4 per-voice LFOs, and 2 global LFOs. The MSEG modules are envelope modules with 32 flexible segments instead of merely 4 (ADSR). Furthermore, Zebra2 also features 4 assignable XY pads, which are helpful during live performance to control multiple parameters at once.
You’ll find 21 effect processors in Zebra2. These include modulation FX, reverb, delay, compressor, parametric EQ, filters, etc. And you can apply up to six effects on either the master channel or on the 2 busses.
Zebra2 has a 16-step sequencer that functions similar to analog sequencers. You can create complex arpeggios using not only notes but up to two-parameter modulations per step. Using the glide feature along with modulated filters can create growling basslines or elegant, evolving arpeggios in no time.
The plugin is available for Windows 7 or higher 32-bit or 64-bit, macOS 10.9 or higher 64-bit only, and Linux. It comes in VST 2/3, AU, and AAX formats.
You can probably tell how gigantic Zebra2 truly is, and the sheer scale of it makes it intimidating to most people. However, the attempt to keep Zebra user-friendly is still laudable. Since it uses a modular workflow, you will not see all of the parameters simultaneously. Instead, you can focus on merely what you need. So, Zebra2 can remain as simple or as complex as you want. Furthermore, the sound of Zebra2 is exceptionally smooth and sounds “realistic.” So, I would suggest it for softer music genres, film scores, media sound design, etc. Overall, it’s one of the absolute best synths on the market.
The 3 Best Free Modular Synth Plugins 2021
1. Sonigen Modular
Sonigen Modular is a capable modular synth with an interface that just makes sense.
This plugin functions quite similarly to hardware. You can right-click on the work area to add a new module and patch virtual cables between modules as you need by right-clicking the modules. I also liked how you can click on the cables to make them loose or taut. Furthermore, the lack of having to assign midi inputs manually makes the plugin much easier to comprehend for beginners.
- Sound Generators
There are six generators in the plugin: Pulsaw, Wavetable, Supersaw, Syncrocs, Noise, and Polysine. You can also edit the Wavetable by clicking on the Edit icon, which I found super impressive for a free plugin.
You’ll find two filter plugins: multi-filter and comb filter. The modes in the filters are comprehensive. And you’ll also find two effect modules: delay and chorus. You can sync the delay to your DAW without having to route a midi clock. And finally, there are two modulators: envelope and LFO. There is also a Controller classification of modules featuring Velocity, Keymap, Note Random, etc.
There are three color codes for the cables, and you can easily assign a color to each cable by right-clicking them. Similarly, you can click and drag the cables to change their shape (for cable management). Unfortunately, you can’t drag and drop cables from outputs to inputs; instead, you have to right-click the modules and select inputs from a list. It’s probably the only disheartening thing about this plugin, although it’s not a deal-breaker.
The plugin is available for Windows 7 or higher 32-bit only. It comes in VST 2 format.
If you are on the lookout for a free, genuinely modular synth that resembles hardware, Sonigen Modular is your best bet. It’s a very usable synth too. There are plenty of presets, and analyzing them will help you learn the synth quickly. Unfortunately, the synth doesn’t have a resizable interface, though. Complex setups can get tedious when you have to use the scrollbars. Still, I would undoubtedly recommend the plugin to beginners and people on a budget.
As crude as the interface looks, its capability remains apparent.
KX-Synth-X16 is based on a vintage hardware synth called VCS3 by Electronic Music Studios Ltd. It was renowned as a powerful electronic effect generator (whooshing sounds and the like), partly due to its lack of tuning stability. However, KX-Synth’s software interpretation of the synth is very much usable as both an instrument and an effect generator.
Let’s acknowledge the elephant on the interface: the matrix. If you have used similar plugins before, you’ll find it easy to get used to. The rows show the various sound sources, whereas the columns represent the signal and control inputs.
- 3 Oscillators
Out of the three oscillators, the first one can generate sine and saw waves, whereas the latter two can generate pulse and triangle waves. You can control the level of each waveform and introduce ring modulation via the matrix too, which is an easy way to make complex sound designs. Furthermore, there is a dedicated noise generator as well.
There is a dedicated amp envelope and a modulation envelope. Both are virtually identical and feature the standard ADSR parameters along with an offset parameter. Similarly, there’s a standard filter module and an FX module with a delay effect.
The plugin is available for Windows XP or higher 32-bit and 64-bit and macOS 10 or higher 64-bit. It comes in VST 2 and AU formats.
I wouldn’t recommend KX-Synth-X16 to learn modular synthesis as it barely even resembles one. However, try it out if you wish to explore a new synth with a vintage sound that could inspire you.
3. Soonth Blocks
Getting started with modular synthesis has never been this intuitive.
Soonth Blocks is a synth that makes modular synthesis as easy as building Lego blocks. The interface features seven rows and columns, where you can add your “blocks” of oscillators, filters, and modulators. The workflow is simple: the columns represent the signal channels, the rows represent the signal chain, and drag and drop modulators over other blocks to modulate them.
All you have to remember is that to process a block (say, an oscillator), you need to place the effect block (like a filter) below the first. And you can also drag each block’s edge to expand it horizontally. Doing so will increase how many columns the block covers. It’s useful when you wish to add a filter or effect to multiple oscillators. And finally, if you no longer need a block, drag it out of the work area to delete it.
- The Blocks
Soonth Blocks features five oscillator shapes: saw, sine, square, triangle, and noise. Each oscillator also has up to 8x unison. Similarly, there are two modulators: LFO and envelope. And there are three effects: filter, reverb, and delay.
The plugin is available for Windows 10 or higher and macOS 10.14 or higher, both 64-bit only. It comes in VST 3 and AU formats.
Considering that you can add up to six oscillators, Soonth Blocks is rather impressive. However, it’s effortless to use. So, if you want modular freedom but free of cables, give Sooth Blocks a try. My only complaint is that you cannot view the parameters of multiple blocks at once.
The 3 Best Semi-Modular Synth Plugins 2021
1. KiloHearts Phaseplant
Phase Plant is one of the most reliable toolboxes of sound creation.
The UI of the plugin is organized into three sections: generators, effects, and modulators. The signal from the generator portion is sent to the effects, which you may route to any lane in the plugin. Phase Plant’s generators feature all the basic settings like unison, detune, macros, and polyphony. However, the fun starts when using the generators’ other modes like sampling and combining them with effect modules.
- Sound Generators
There are four kinds of generators in Phase Plant: analog, noise, sampler, and wavetable. The wavetable generators let you use custom wavetables as well. And the sampler can both record audio and use pre-existing WAV files. Mixing multiple types of generators is one of the primary starting points to sound designing in Phase Plant.
KiloHearts’ effect plugins are called snap-ins, and you can load any of them to your signal chain in Phase Plant. There are three “lanes” for the effects. Each lane acts like a bus, where you can send signals from the sound generators. And if you load a preset that utilizes a snap-in that you don’t own, the preset still works, but you won’t be able to modify the parameters of the snap-in. I love that they don’t cripple the synth to force a purchase.
At the bottom of the interface, you’ll find an envelope, LFO, MIDI control, macro-control, multipliers, randomization modules, etc. Interestingly, the LFO lets you make new waveforms in this section and even use it as an envelope. It’s super helpful in creating evolving soundscapes.
This plugin is available for Windows 7 or higher and macOS 10.7 or higher in VST 2/3, AU, and AAX formats.
Phase Plant comes in three flavors where one is the basic edition that ships with the free KiloHearts snap-ins. The Subscription and Ultimate models provide you every KiloHearts plugin in a bundle, including the VST/AU/AAX versions of the snap-ins. I think most sound designers will want the ultimate edition to create elaborate sounds, but if you are just starting, the basic version is a great place to start. Overall, Phase Plant is a highly flexible synth.
2. Madrona Labs Aalto
Aalto is an efficient semi-modular synth plugin that can sound lush or edgy as you want.
A “complex oscillator” influenced by Don Buchla’s designs lies at the core of Aalto, with FM, timbre, and waveshape settings that allow for a broad range of expressive sounds. These sounds are particularly flexible and lively, thanks to the use of dynamic calculations instead of static wavetables.
The resizable interface features the modulators at the top and the oscillators at the bottom, while the middle part displays the routings. The small dots are the outputs in the routing section, whereas the small knobs are the input levels. At first glance, it appeared rather complicated, but I did get used to it soon enough.
- Frequency Modulation
When Madrona Labs say complex, they mean it. The Complex Oscillator is a true FM synth oscillator with both Modulator and Carrier oscillators. The module features Noise, Ratio to adjust the frequency between the Modulator and Carrier, and Offset to add a constant offset to the Modulator’s frequency. Furthermore, Mod Index lets you set how much the Modulator modulates the frequency of the Carrier oscillator. It also uses a low-pass filter called a “vactrol,” which uses an LED with a light-sensitive resistor to control voltage. I would honestly suggest you skip worrying about these and use your ears instead. In essence, the filter makes the sound feel more organic and flawed.
- Sequence And Movements
The plugin features two envelopes, an LFO and a sequencer. While most of these are standard modulators, you can add extra movements to the LFO by adding noise. Similarly, the sequencer can control the pitch like a regular analog sequencer or control parameters instead. Furthermore, the animations on the interface help display the effect of the modulations in real-time.
One would expect to come across some sense of familiarity here finally, but alas, Aalto has other ideas. It features a filter with low-pass/band-pass/high-pass, a basic reverb, and a delay. Except, the delay isn’t a delay because of its extremely short feedback time, essentially making it another oscillator.
The plugin is available for Windows 7 or higher and macOS 10.9 or higher, both 64-bit only. It comes in VST 2 and AU formats.
Being an adventurous sound designer, I admired the grounds Aalto covered instead of staying traditional. However, if you aren’t into experimentation, you might find this plugin way too complicated to comprehend. Thankfully, though, each parameter makes an audible difference, so you can also create patches using your ears. Still, it may be slightly less appealing, especially when you consider its CPU-heavy processing.
3. SYNTHMASTER V2.9
SynthMaster is one of the most notorious synth plugins on the market, thanks to its flexibility and excellent sound.
People love SynthMaster for the variety of sounds it can produce. And it’s evident in the plugin’s gigantic collection of 1800+ presets. The variety comes from its multiple synthesis methods. Combine that with the included high-quality filters and effects, and you’ll have a complete environment for sound production.
Furthermore, another one of its notable features is the powerful arpeggiator, which can act as an integrated piano roll in addition to basic up, down, up-down, etc., modes. The sequencer can have up to 32 steps and has velocity, note length, slide, hold, etc., parameters per note.
- Synth Modes
SynthMaster employs Subtractive, Additive, Wavetable, Phase Modulation, Frequency Modulation, Pulse Width Modulation, Ring Modulation, Amplitude Modulation, Physical Modeling, and SFZ Samples Playback synthesis. Each features an abundant number of waveforms, features, and controls. For example, even a basic oscillator comes with 17 algorithms in many categories.
- Double Layer
A layer acts like a track that can send to two global effects sends. Each layer can feature an arpeggiator, two oscillators, four modulators, two filters, two LFOs, eight envelopes of various kinds, and four key-scalers. The envelopes include four standard ADSR envelopes, two multi-stage envelopes, and two 2D envelopes. Hence, an instance of SynthMaster features all of these twice over.
SynthMaster features four kinds of filters: VAnalog Filters, Multimode Filters, Dual Filters, and Comb Filters. The Dual Filters support running two multimode filters simultaneously in parallel or series.
Finally, you can insert five effects on each layer and also two in the global effect bus inserts. There are 11 kinds of effects in SynthMaster: reverb, delay, chorus, tremolo, vocoder, compressor, 6-band EQ, phaser, ensemble, Lo-Fi, and distortion. Interestingly, you can also add distortion before, after, and inside the filter, which helps sell the analog sound even more.
The plugin is available for Windows 7 or higher and macOS 10.9 or higher, both 64-bit only. It comes in VST 2/3, AU, and AAX formats.
Other than the features listed above, SynthMaster also features micro-tuning, an excellent preset browser with multiple search criteria, online presets from other users, and multiple skins. Similarly, you can import MIDI files as arpeggiator sequences and WAV/AIFF files as SFX definitions. So, as you can see, SynthMaster is a massive synth and can potentially be your most valued investment in terms of sound variety and playability.
VCV Rack (Free App)
Revive the sound of the famous Eurorack using this incredible free software.
VCV Rack is an ever-expanding modular synth that currently features over 2,700 modules in its library. Unfortunately, so far, the software is standalone only, but the upcoming version (expected in November 2021) is set to launch as a VST/AU/AAX plugin for both Windows and macOS. However, the launch will result in two versions: Community and Studio Edition. While the Community edition will remain a free product, the Studio edition, which is the plugin version, will cost you $150. However, considering the thousands of modules it features, the price feels like a steal.
- Deeply Modular
Just like hardware modular synths, VCV Rack also uses the same concept from the ground up. For instance, you need a VCV MIDI-CV module to connect midi signals to your oscillators. Similarly, you can connect inputs and outputs using drag-drop to create virtual cables between modules.
- The Modules
There are two kinds of modules in VCV Rack: Core Modules and Add-ons. The Core Modules include MIDI-CV, CC, Gate, Map modules. These come with the rack itself. The add-ons are the modules that create and manipulate the sounds. Unfortunately, I cannot describe the modules here as there are far too many to even list. So, you’ll have to trust me when I say there’s literally everything we need and way more.
The standalone software synth is available for Windows 7 or higher, macOS 10.7 or higher, and Linux (Ubuntu 16.04 or higher), all in 64-bit only.
VCV Rack is an outstanding way to learn and experiment with modular synthesis without spending. While there are other similar synths like Cherry Audio’s Voltage Modular, none of them come close to the scale of VCV Rack. You’ll find hordes of presets and tutorials online to learn more about it too. So, if making new sounds and playing them is a hobby for you, I highly recommend this software.
Modular synths are truly liberating to use, and they can inspire a whole new world of music for every kind of music producer. And since most of them are highly efficient, there isn’t a set rule for choosing the perfect collection for you either.
Even so, I will write a few broad guidelines. If you prefer making EDM, hip-hop, trap, etc., I suggest synths that naturally produce dirty sounds like Sugarbytes Factor, Unfiltered Audio Lion, KiloHearts Phase Plant, and Tracktion Hyperion. While they’re all pretty efficient at creating a variety of sound, the interface and the filter types strike me as modern and digital.
Similarly, if you are into softer music or film scores, u-he Zebra2, Reaktor 6, and AAS Multiphonics are excellent options. SynthMaster, Softube Modular, and u-he ACE are ideal for either type of music production.
And finally, if you are a beginner, I highly suggest starting with Soonth Blocks and moving on to VCV Rack. After that, you can try out the free Sonigen Modular or consider purchasing a synth from the list. And on that note, we reach the end of this article. I hope it has helped you pick a modular synth for your next step in music production.
K. M. Joshi is a multi-award-winning composer and sound designer, specializing in film, game, and TV audio. He enjoys making cinematic music, rock, blues, and electronica.