11 Best Additive Synth VST Plugins 2025

Additive synths are complex and sophisticated. Because of that, they’re often powerful, versatile, and even realistic sounding.

But finding the right one isn’t just a matter of picking out the most expensive. From CPU usage to OS compatibility, you must be intentional in tracking down a synth that’s going to meet your specific needs.

Not to worry, though, because you are in the right place at the right time. In this guide, we look at the best additive synth VST plugins as well as which will work in what situations.

Loom II by AIR Music Technology – Best Overall

AIR Music Technology’s Loom II is a revelation compared to the original Loom, pushing additive synthesis to entirely new levels. But it’s simple enough that even a newbie can figure out how to use it.

Some of the latest additions to the award-winning modular additive soft synth include eight voices, Spectral Noise section, four new modules, two additional Subharmonic Partials, enhanced Morph Pad options, 500 new patches, New Wave parameter options, the original 350 patches remastered, and over 20 other performance enhancements.

Loom II also comes with over 750 patches programmed by legendary sound designers, Smart Sound Randomizer, 34 editable sound modules combinable in 10 cells, Economy mode, and more.

There are 14 categories of presets in total, including Meet Loom 2, Leads, Basses, Wobble, Pads, Moving Pads, Atmospheres, Polys, Organs, Bells, Percussive, Swells, Waves, and SFX.

Overall, this is a nicely designed, versatile, great sounding synth with a ton of presets, and it’s available for Windows and Mac.

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Synclavier V by Arturia – Best Premium Option

Based on the original digital synthesizers / workstation that epitomized the 80s sound, Arturia’s Synclavier V is a must-have for composers, songwriters, and producers alike.

This digital synth is known best for its aggressive, brash, and edgy digital tones. While it can do warm and subdued, it’s in its element when it’s modern and intense.

Synclavier V features 450 presets, FM (frequency modulation) synthesis, full additive synthesis with time slice engine and additive waves for carrier and modulator waveforms, 12 partials (eight more than the original), variable bit depths, output effects, algorithmic reverb, and compatibility with the original Synclaiver library.

The Synclavier V features a ton of great sounds, the kinds you’ve heard on Tangerine Dream, Michael Jackson, Sting, Frank Zappa, Pat Metheny, Chick Corea recordings, and more. Whether you need a Synclavier replacement or a phenomenal additive synth, you’re barking up the right tree.

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Harmless by Image Line – Best Budget Option

The little brother of Harmor (also seen in this guide), Image Line’s Harmless is rather unique in that it’s an additive synth “doing” subtractive synthesis.

In setting out to create this entry, Image Line didn’t want to create just another subtractive soft synth. They wanted to create a digital synth, plain and simple, instead of a virtual analog one (which are available in droves).

The developer even adds a bit of humor to their product description, saying “everything is fake.”

Harmless lets you take control where many subtractive synths don’t, with filtering and phasing that can be assigned unusual shapes and slopes. You've also got control over each partial’s frequency.

Harmless’ CPU usage has been optimized, and it comes with 100 mostly automatable parameters (no hidden settings), LFO section with modulation source options, and effects (like chorus, reverb, delay, multiband compressor / limiter, and more).

Harmless is only available for Windows.

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Harmor by Image Line

Harmor is an additive / subtractive synthesizer, image synthesizer, and audio resynthesizer.

As the more powerful bigger brother of Harmless, Harmor features oscillators, filters, phasers, much like a subtractive synth. But because you get to select and draw filter types, you’ve got far more flexibility with Harmor than with other alternatives.

Imagine Line also included a multipoint envelope editor with two parts and over 40 parameters. You can use the envelope / mappings to randomize parameters, link it to velocity or key, and tune each unison voice individually. With a semi-modular design, you can even arrange processing units as you see fit.

Manipulating up to 500 envelopes per voice sounds like an impossible undertaking (which it is), and that’s why Image Line added gain and pitch planes in the image editor to let you take full control of additive synthesis. You can even import bitmaps.

The onboard resynthesis features let you time stretch and pitch shift, and results can even be turned into images for additional editing.

Harmor is CPU engine friendly where most additive synthesizers aren’t. It features two independent layers, an effects section (with chorus, distortion, reverb, and delay), Soundgoodizer, and more.

This flexible synth can do more than simple square and saw waves, and as you might expect from the developer, it’s a killer tool for electronic music production.

If you’re a Mac user, though, you’ll have to pass on this one, because Image Line’s Harmor is for Windows only.

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Morphine by Image Line

One of the greatest struggles of any producer or keyboard player is recreating a sound they’ve heard on a recording or even in their head. Image Line, however, promises that their Morphine synth will remove much of the pain involved in finding that magical “sweet spot.”

How does Morphine help you arrive at your destination faster, though? First, it lets you adjust the harmonics manually. Second, it gives you the ability to take an input sample and resynthesize it into one of four individual voices.

Morphine features a CPU friendly algorithm, a 128 harmonic oscillator engine, optimized oscillators with fast amplitude and frequency modulation response, morphable generator sources (using the mix / morph envelope or with a MIDI controller), found multipoint modulation envelopes, and more.

Altogether, you’re getting four independent generators per voice, keyboard layering with 128 Keyboard Zones, unlimited harmonic snapshots per spectrum, amplitude, detune, and panning, filtering and velocity response, manual override for resynthesis, and an import feature (for waveshapes).

You’re also getting variable-time control for spectra, mix / morph envelopes, four PWM filters, additional generator with noise sample, morphing path, morphing square, one to 32 note polyphony, ADSR master envelope, adjustable velocity response, five built-in simultaneous effects (chorus, reverb, delay, equalizer, distortion), and more.

Morphine is only compatible with Windows.

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FRMS – Granular Synthesizer by Imaginando

In case the word “granular” caught your attention, you’ll be happy to know that Imaginando’s FRMS – Granular Synthesizer is in fact a hybrid soft synth. This is a great tool for turning simple sounds into complex soundscapes with movement.

FRMS – Granular Synthesizer gives you the option of combining up to four layers of synthesis (granulator or oscillator) and granulating any input.

Overall, FRMS comes with over 150 presets, four synth engines and four layers per voice (FM, granular, additive, subtractive), eight FM modes, sample and live audio granulating, 20 grains per layer, one modulation matrix per layer, two EGs per layer, one filter per layer and master filter, and four voice polyphony.

You also get four LFOs with five modes, arpeggiator with five modes, reverb and delay FX as layer send, sample bank, and a built-in audio recorder.

Additionally, FRMS is MPE compatible and comes with lifetime free updates.

Whether for electronic music, scoring, songwriting, or otherwise, FRMS’ potential is expansive.

FRMS is Windows and Mac compatible.

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Vecto by Rob Papen

Not an additive synth specifically (it comes with additive waveforms), Rob Papen’s four-oscillator vector synthesizer, Vecto, is a ton of fun, is loaded with neat features, and is full of personality.

With Vecto, you can draw in vector paths to shape the sound. You’ll find many oscillator waves, sampled waveforms, preset vector paths, and multiple modulation options included.

Overall, Vecto comes with 1,300 presets, granular resynthesis of the samples (with grain on / off, grain size, length, randomization), XY controller, 28 filter slots, two effects processors, various waveforms (classic analog models, additive, spectrum, samples), and arpeggiator.

As you’ll surely be able to tell from the video below, Vecto is great sounding and very versatile.

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Sytrus by Image Line

When it comes to additive synths and variations thereof, Image Line may well be the king. And the Sytrus name is familiar even to those who might be a stranger to FL Studio.

Sytrus comes with six user-definable operators which can be set as independent oscillators or subtractive synthesis. You can cross-modulate for FM or RM synthesis; you can even use the 256 partial harmonic editor for additive synthesis.

The synth also features up to 64x oversampling, three chainable filters (13 types each, five cutoff slopes), integrated waveshaper (distortion processor), three-band parametric EQ, reverb, delay, chorus, and 500+ presets.

Finally, there’s also multipoint articulation with arpeggiator and an X/Y modulation control.

For electronic music, Sytrus is considered a must-have, and it’s not hard to see why. This thing sounds great!

Sytrus is available for Windows only.

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Phosphor 3 by Audio Damage

Audio Damage’s Phosphor 3 takes after the 80s digital additive synth, alphaSyntauri. The original required the use of an Apple IIe computer, but for this development, Audio Damage did away with such limitations.

The third iteration of Phosphor improves upon its predecessors with more modulation options, MPE support, TUN-file support, and a new preset browser.

Altogether, Phosphor 3 features two voices (with wavetable oscillator, transposition, fine-tuning, noise generator, level, ADSR, delay line with filter, level, pan), additive wavetable oscillators with 16, 32, or 64 partials (with level sliders, presets for common waveforms, partial level randomization), and noise sources.

You also get two ADSRs, vintage modes, two LFOs, modulation, dual delays, voice modes, T-Rand modulation, and factory presets.

Phosphor 3 sounds nothing short of stunning, with a wide range of fun sounds to tap into. This much synth for this little can be hard to find, making this a great budget pick. It’s not an additive synth strictly, but it’s hard to argue with this much versatility.

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Predator-3 by Rob Papen

With versions one and two becoming big hits among composers and artists, developer Rob Papen set out to create Predator-3, a powerhouse soft synth with over 6,500 presets, new arpeggiator features, multi envelopes, audio follower input, sidechain control, and an analog modeled sound code.

Predator-3 includes three GUI sizes (100%, 133%, and 200%), three oscillators with sub-oscillators, subtractive analog modelled waveforms, additive spectrum waveforms, eight user spectrum waveforms per preset, morphing, Spread feature, audio modulation with oscillators 2 and 3, and diverse routing options.

In terms of filters, you get two analog modeled filters with routing options, 38 filters, pre-filter distortion, filter envelope (with attack, decay, sustain, sustain-fade, and release), and an additional high pass filter with resonance (Q).

You’re also getting a bevy of other features like a recordable XY pad, pitch LFO, filter LFO, envelopes, multi-envelopes, modulation matrix with 20 slots, EQ, 34 FX types, and more.

While it’s not an additive synth exactly, Predator-3 does come with additive spectrum waveforms. And, it also sounds amazing, as evidenced in the video below.

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Farfisa V by Arturia

Arturia’s Farfisa V, of course, takes after the legendary Farfisa combo organs that took over the airwaves in the 60s. Arturia used their proprietary physical modeling technology to bring this classic to life. No sampling.

Many people like to think of the Farfisa as a hybrid organ-synth. The original came with a rudimentary envelope, key repeat, split keyboard, and a knee lever for manual control of filters.

Arturia went beyond that, though, and with Farfisa V, you can create your own additive waveforms, choose different waves for the bass sections, set offset filters, customize envelopes, and more. You’ll even find a collection of vintage amps and old school stomp box effects.

In total, you get upper manual, lower manual, and bass pedal selections, selectable bass key range, bass sharp / soft control, percussion section, drag-and-drop effects, guitar amp sim, convolution reverb, Sync (for tremolo), repeat sync, individual voice tuning, and Tone Draw.

You also get a selectable bass waveform with four-pole resonant filter, user waveform with additive synthesis and wavedrawing, upper attack and release envelopes, knee lever, polyphonic or paraphonic operations, and MIDI support.

If you’re looking for a vintage, hybrid organ / synthesizer, then this one might just float your boat.

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What Should I Look For In An Additive Synth VST Plugin?

Having come this far into the guide, you’ve had the opportunity to check out a variety of additive synth VSTs and those with additive capabilities. Your options are somewhat limited if you’re looking strictly for additive synths but expand a bit if you add in a few hybrid synths in there (which we covered towards the end).

Here are a few things worth considering when shopping for an additive synth VST:

• Sound quality
• Compatibility
• CPU usage
• Features
• Budget

Let’s take a quick look at each.

Sound Quality

Virtual synths nowadays all tend to sound quite nice (some even stand the test of time 10 years later), but of course different products have different capabilities. There are many vintage analog modeled synths, and there are some digital synths too.

If you know your way around synthesizers, I probably don’t need to say a word more. But if you’re stuck on which product to buy, then here’s a tip:

Narrow your options down to three to five synths. Then, listen carefully to each. There are plenty of video demos, video reviews, and sound clips out there. Studying each synth should give you a better idea of how each of them sound.

Then, choose what you think is going to work for you. You probably have some idea of the projects you’re going to be working on (a better idea than just about anyone else), so it’s okay to purchase based on individual preferences. Chances are you’ll be more satisfied with the product that way too.

Compatibility

Image Line creates some great additive synths, but as you’ve already seen, most of their products are not Mac compatible. That being the case, you will need to purchase based on OS compatibility to avoid unnecessary heartache.

CPU Usage

Because of the way additive synth VST plugins work, they can be a little resource heavy. It seems like most developers have solved this problem, but just in case, it’s well worth checking product specs and system requirements before purchase.

This is especially true if you have an old computer.

Features

Not all synths are created equal. Study what each synth comes with. If you know what you need, you don’t need my help. Otherwise, it’s worth spending some time in research to better understand what you’re buying.

Budget

Don’t overspend or go into debt! Use your budget as a filter for VST purchases.

Top Additive Synth VST Plugins, Final Thoughts

Now you know everything you need to know to find the perfect additive synthesizer VST plugin for your needs. Take your time, listen to each synth, do your research, and you should end up with a product you’ll be totally satisfied with. Have fun!