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 Fathom Synth by Seaweed Audio is a Virtual Instrument Audio Plugin. It functions as a VST Plugin and an Audio Units Plugin.
Fathom Synth
Product Fathom Synth
Developer Seaweed Audio
Price (MSRP)
Free (Mono) / $80.00
Type / Tags
Plug-in, App & Soundware Format(s)
Operating System Availability
Download Released
Downloads Released
Downloads Released
Supported Sample Formats (loads or saves) include
Audio Demos
Miscellaneous Information
Copy ProtectionNone

Fathom Synth Website:


Version 2.10.7 Released

This release contains important bug fixes for Windows and Mac.

Version Changes

PayPal 48 Hour Delay

Please be advised that if you use PayPal and are outside the mainland USA, there is a 48 hour delay on receiving your order. The delay is due to tighter security policies invoked recently by PayPal. If this happens to you please send a PM so we can issue you an temporary license.

Why is the payment I received under review by PayPal?

The delay is not caused by KVR or Seaweed Audio.

Supported Plugin Formats

Fathom supports Windows VST 32 (Fathom32.dll) 64 (Fathom.dll), Mac AU (Fathom.component) Mac VST (Fathom.vst).


Fully Modular, 16x16 Wave Table Morphing, Free Hand Wave Draw, Bezier Curve Oscillator, Single Cycle WAV Import Export, 5 Alias Free Oscillators, 30 Filters, 6 Effects, Bezier and Exponential Envelope Curves, Unlimited Modulations, 7 Types of Modulators, Real-time Host Automation, Resizable GUI, Free Mono Version, Direct Email Tech Support, Windows and Mac compatible.

Fathom Makes the Front Page of BPB Top 50 Free VST

BPB Top 50 Free VST Plugins of 2017

Read the BPB Magazine Review of Fathom

Bedroom Producers Blog Magazine Review

KVR Marketplace Purchasing Instructions

KVR Purchasing Instructions

New Fathom Video

Wave Morphing Utopia

Fathom Pro on Sale for KVR Members Only:

The members page is now by direct link only, password kvrpro.


Version Update Downloads


Fathom Synth:

Fathom is a new fully modular software synthesizer designed to meet the growing demand of producers and musicians to create original waveforms and complex modulations.

Wave Table Morphing Oscillator:

Two morphing tables of 16 waveforms each with modulating wave indexes for real-time wave scanning.

The ability to modulate and morph between the two tables creating a 2D scanning array.

Waveforms in the second table can be added or subtracted from the first.

Algorithms include morph, add and subtract, unipolar, bipolar, chop.

Animated graphs show the operand waveform, operator waveform and combination waveform in real-time.

Each waveform can be loaded or hand-drawn using the wave draw interface.

Waveforms can be auto-filled for perfectly smooth transitions between edited wave positions.

Individual waveforms can be saved and loaded, and entire wave tables can be saved and loaded.


Fully modular signal flow.

7 different types of oscillators including 5 alias free oscillators.

Bezier Curve and Wave Draw Oscillators.

All oscillators include:

  • AM and FM synthesis.
  • Frequency ranged noise generator with built in filter.
  • Harmonic and random distortion section.
  • Detune section with nonlinear modulations and built in chorus.

32 different types of filters.

6 effects including two chorus, two reverb, phaser, digital delay with 3 channels, built in filters, feedback, and multiple sends.

Modulators: LFO, LFO Draw, ADSR, Multisegment Envelope, Sequencer, Random Sample and Hold, Keyboard Tracking and MIDI control, with up to 64 segments per envelope.

Modulation matrix: unlimited modulations per dial, unlimited dials per modulation.

Exponential and Bezier envelope curves.

The ability to draw your own waveforms.

The ability to export your own waveforms to wav format (pro version only).

Host automation of virtually every control on the instrument.

Over 400 factory presets and 200 waveforms.

Latest User Reviews Average user rating of 4.29 from 7 reviews

Reviewed By djkybernetik
January 16, 2018

I love this Synth. It has cool Features and i thank Everett from Seaweed Audio very much for his great Support to run the Plugin on my (older) Mac.

The Modular Concept is powerful to create fantastic new Sounds. I'am since my Childhood an great Fan of Jean-Michel Jarre so i like many innovative and flexible Synthesizers (old analog and newer).

I can only advice to try the Demo (Free Mono) Version.

Best Regards.


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Reviewed By ReverendLove
January 8, 2018

It's my first review because I am really amazed by this system.
This one is excellent. The workflow once you read the manual is so logical and beautiful designed that it really stands out in the modular system crowd.
First I thought the modulation matrix is somewhat crowded but after reading I wondered why others don't do it that way. The possibilities are endless.
The automation system is so easy that I really did not get it. Click on rulers label and it's there. Wonderful.
OK, from my personal aesthetics' point of view the graphics' design is not my cup of tea and looks a little bit "toyish".
So no real concern. But the layout itself cannot be better.
The only thing I miss is an input for using it as FX chain.
The sound of the oscillators are stainless and building with the modules is absolutely intuitive. Left in, right out, that's it.
I'd exactly no bad issues with Fathom.
Great work.
I feel a little bit guilty for thievery getting this for 5$ on New Years Day so I wrote this serious review..

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Reviewed By jmg8
January 7, 2018

Very powerful and clean sounding OSCs. Nice per voice distortion and detuning options. Good modulation options.

This is a very deep synth with lots and lots of option, however, at the same time, it has quite a clean GUI that is easy to use.

The developer has excellent customer support with very regular updates.

Exceptional value for money.

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Reviewed By levendis
December 20, 2017

Uncapped modulation options and hybrid functions housed in simplicity. Some exotic interactions between components of its modular architecture too. The oscillators hybridise with other oscillators for AM/FM synthesis, with the phaser (spelled 'Phasor' in Fathom) for unison-like voice generation, and the wavetable oscillator offers a giant pool of possible timbres. Multi-stage envelopes with modifiers that impose gating of variable width and position adds another dimension to articulation. The delay unit is so good it can serve in the reverbs' stead.

For balance, drawbacks of note is its demand on CPU, due to its sample-accurate signal processing. Of course, the sonic potential is compensation. There's some room for improvement to its ergonomics too, but as development continues i have faith these will become more efficient.

Fathom is substantial despite appearances. A deceptively priced softsynth for the sound.

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Reviewed By connmach
September 6, 2017

A logical, powerful, creative and musical soundcrafter.

Beautifully made. Highly recommended.

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Discussion: Active


Scrubbing Monkeys
Scrubbing Monkeys
13 August 2017 at 9:26pm

I have been using Fathom for only a few months now. I started on version 1.0.7. At this point it is up to 1.0.11. It has a bucket load of features but a few that really grab me are the extremely powerfull envelopes and the built in delay. You can not only draw your envelopes but can double, triple............ and so on giving you a sequencer type feel. The delay is a three headed monster giving you COMPLETE control over left, right and center. This synth is capable of just about everything out there with alot of stuff we havent seen. I can see this being used alot for evolving soundscapes and one finger rhythmic dances. At this point it has a firm direction, is stable and a pleasure to program. Looking forward to the finer details.

2 January 2018 at 10:29pm

Good blueprint, bad usability.

My score is 6.00.

11 January 2018 at 12:05pm

Trying to buy at discount price of $15 which is supposed to be available until 31st Jan 2018 but when I checkout it goes to full price ? Help please.

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Fathom Synth

Average user rating of 4.29 from 7 reviews

Seaweed Audio
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