BEST OF 2021: For computer musicians, a good synth plugin is likely to be the beating heart of any software-based studio setup. A quality virtual synthesizer is right up there with a Digital Audio Workstation (DAW) in terms of must-have tools for electronic musicians, and the style, features and capabilities of your chosen synth(s) can go a long way towards shaping the sound of the music you create.
As is the case with most forms of music software, there’s a plethora of options out there, including numerous so-called ‘freeware’ instruments that can be downloaded without being paid for.
You might, understandably, assume that these free synths are always inferior to their paid-for counterparts but - as many of the instruments below ably demonstrate - that’s not necessarily the case. In terms of their sound and capabilities, many of the free synths on this page could easily go toe-to-toe with a lot of commercial synth plugins.
That’s not to say there aren’t potential downsides to relying on freeware instruments. While the core features of free plugins are often excellent, they may not offer some of the niceties of their paid rivals, such as extensive preset libraries, onboard effects or regular updates.
The most significant risk with freeware synths is that you can’t always count on long-term support and upgrades, meaning that free synth you love may not keep pace with the changing needs of your DAW or operating system.
That being said, many freeware instruments - particularly those that are open-source - are lovingly maintained and developed either by their original creators or a community of users.
As with commercial plugins, freeware synths come in all shapes and sizes. Some emulate or clone the sound of classic hardware instruments, while some are original designs of their own. In the list below you’ll find a variety of synthesis types, from virtual analogue to FM, wavetable, modular and hybrid instruments that combine multiple approaches.
One of the great things about freeware is that it gives users the opportunity to try out these different types of synth design for free, so if you’re not sure which is for you, why not try downloading several styles of synth to see what suits you best?
The only other factor to consider is compatibility. We’ve listed with each synth what operating systems it can be used on, and available formats (standalone, VST, AU or AAX). Your needs here will depend on your chosen DAW, so make sure you check up on what plugins yours can host before downloading.
The best free VST synth plugins
PC/Mac | Standalone/VST/AU
OB-Xd isn’t the flashiest synth is this round-up, nor is it the newest, despite being updated to version 2 in recent months. It remains our favourite freeware synth, though, based largely on its blend of simple usability and excellent sound.
This is an emulation of Tom Oberheim’s classic OB-X polysynth, an analogue classic beloved for its thick, rich sound and easy-to-use interface. OB-Xd lives up to its inspiration on both fronts. Sonically, this is up there with many paid analogue emulations and, while it lacks the bells and whistles of something like Arturia’s V Collection synths, OB-Xd does build on the design of the original with a morphable filter design and voice variation controls.
While other freeware synths on this page are undoubtedly more adventurous or original than OB-Xd, none are likely to match the broad appeal of this excellent virtual analogue. Download it now and it could quickly become your go-to for rich, vintage poly sounds.
2. VCV Rack
PC/Mac/Linux | Standalone only
It’s debatable whether VCV Rack should be counted as a virtual synthesizer or a DAW in its own right. While it is, essentially, a digital recreation of a full, customisable modular synth, it can also host plugins of its own, mix and export multiple audio channels and be used to create full track arrangements.
The downside of its DAW-like character is that it can’t be used as a plugin within any other application, although a paid-for plugin version is in the pipeline.
As a self-contained synthesizer, however, there’s a lot to love about VCV Rack. It’s free and fully open source, and the already-powerful core lineup of included modules can be expanded using a community-created library of both free and paid-for plugins.
As a tool for users looking to discover or learn modular synthesis, or spec-up a real world Eurorack system, VCV is invaluable.
PC/Mac/Linux | VST/AU/LV2
Vital is the newest and one of the most advanced synths in this roundup. This is a ‘spectral warping’ wavetable synth that uses morphable sampled sounds as its oscillators, setting it apart from the virtual analogues that make up the bulk of this list.
The slick UI looks reminiscent of Kilohearts’ top-end Phase Plant power synth, and Vital boasts a host of advanced capabilities including audio rate modulation, stereo LFOs, multiple filter models and MPE control.
Why is such a feature-packed synth offered up for free? Well, Vital uses a model whereby the basic instrument itself is free and offers a largely complete feature set, but it comes stocked with a reduced library of source wavetables (25) and available presets (75).
While this is slightly limiting, there’s still plenty of fun and creativity to be had. Should you find yourself enamored by Vital - which is likely - there are multiple upgrade options ranging from an expanded $25 version to an all-you-can-eat $5/month subscription.
PC/Mac | VST/AU/AAX
Pendulate is described by its creators as a ‘chaotic monosynth’, which provides a decent primer for the sort of sounds you can expect from it; think weird bleeps and FX rather than classic analogue leads.
The instrument takes much of its inspiration from so-called ‘West Coast’ modular synths, specifically those created by Don Buchla. Like those hardware instruments, Pendulate makes use of less common synthesis elements such as a wavefolder and low-pass gates instead of filters.
The star of the show here, however, is the Chaotic Oscillator, which uses a double pendulum design that can morph between simple sine waves and more unusual oscillator shapes.
An animated and customisable UI, MPE support and lots of routable modulation make this a particularly well-equipped freebie synth. A paid upgrade, Generate, is available too, which adds multiple chaotic oscillators and more.
PC/Mac/Linux | VST/AU
Surge first appeared on the scene as a commercial paid-for release in the latter half of the noughties, but it’s been given a second life in recent years after re-emerging as a free and open-source plugin.
Despite its age, this is a thoroughly well-equipped synth with a hybrid engine combining elements of virtual analogue, wavetable and FM sound generation.
The beauty of Surge being open-source is that it can benefit from community development. Recent updates have updated the look and feel of the instrument considerably, as well as modernising it with features such as improved effects, MPE compatibility, a unison mode and new filter models.
Mac/PC/Linux | VST/AU/LV2
Whereas some older freeware synths can look a little dated, or feel rough around the edges compared to their paid-for counterparts, that’s not the case with Helm. This slick and smartly-designed instrument could easily pass for a contemporary, paid-for product, both in terms of its UI and sound.
This feature-packed virtual analogue synth combines straightforward elements such as multimode oscillators and resonant filters, with a few more unusual touches including a formant filter, tuneable feedback and stutter effect. A click-and-drag modulation system makes setting up patches quick and intuitive, and there’s even a neat step sequencer onboard.
An excellent package, bearing in mind the price!
Mac/PC/Linux | VST/AU/LV2
Dexed is, broadly speaking, a recreation of Yamaha’s iconic DX7 synth brought into the plugin realm. In many ways, Dexed not only matches the capabilities of its inspiration - it sounds bang on - but actually improves upon it.
Like many FM synths, the DX7 was notoriously unwieldy to program, but by having the full six-operator synth engine accessible in a single UI window Dexed significantly simplifies the process.
It’s still not the most intuitive synthesizer format for newbies, but since it’s free it’s a nice starting point for anyone looking to investigate FM synthesis. Dexed can also load or export patches compatible with the real DX7, as well as several other FM synths such as NI’s FM8 or Korg’s Volca FM.
Mac/PC | VST/AU/AAX
A true stalwart of the freeware synth scene, NoiseMaker is an evolution of Togu Audio Line’s even older, but equally fondly regarded Elek7ro.
Like its predecessor, NoiseMaker is a virtual analogue synth with syncable oscillators and self-oscillating filters that make it fantastic for gritty vintage basses and leads.
The other ace-in-the-hole here is NoiseMaker’s chorus, which is a solid emulation of the dual-mode effect found on Roland’s classic Juno synths. Plentiful modulation options, plus reverb and delay effects round out the package nicely. There’s an onboard bitcrusher effect too, which makes NoiseMaker handy for arcade and chiptune-style sounds.
Mac/PC | VST/AU
German developer Full Bucket has released numerous freeware emulations of classic synths, and they’re all impressive in their own right. If we have to pick a favourite it’s this recreation of Korg’s late-’70s PS-3300 polysynth, simply because it’s a lesser-emulated synth that will complement your existing virtual analogues nicely.
The original PS-3300 was something of a behemoth, effectively combining three individual monosynths into one massive semi-modular poly. The emulation brings the sounds and all its eccentricities to your DAW. Distinctive features include a bank of resonators for each synth ‘block’, sample and hold generators and even full micro-tuning capabilities for each oscillator. Perfect for Aphex Twin wannabes!
10. u-he Tyrell N6
Mac/PC/Linux | VST/AU/AAX
Tyrell N6 is another staple of the freeware synth world, regularly popping up in lists of must-have freebies.
Despite its stylish UI this is, on the surface, a fairly straightforward virtual analogue synth, with a standard setup of VA oscillators, resonant filters and ADSR envelopes.
What makes Tyrell worth noticing, however, is the pedigree behind it - this is a freeware plugin created by German developer u-he, which is responsible for some of the finest paid synth plugins on the market. While it’s neither the newest nor the most groundbreaking instrument here, the u-he name alone makes it a must download.