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Synth (Semi Modular) Plugin by sjoerdvankreel
InfernalSynth by sjoerdvankreel is a Virtual Instrument and a Virtual Effect Audio Plugin for Windows. It functions as a VST 3 Plugin and a CLAP Plugin.
64-bit windows, VST3 or CLAP capable host.
Copy Protection
Open Source
Important Note
Known issues on Tracktion Waveform related to loading (factory) presets.
My KVR - Groups, Versions, & More
45 KVR members have added InfernalSynth to 13 My KVR groups 51 times.
Not In Your MY KVR Groups
(or group limitation prevents versioning)
+13 in private groups

KVR Rank

Overall: 551   547

30-Day: 1146; 7-Day: 680; Yesterday: 2595

See screenshots for all built-in themes over here: https://sjoerdvankreel.github.io/infernal-synth/screenshots.html.

What it is:

- Open source semi-modular VST3 and CLAP synthesizer and effect plugin.

- Comes with multiple oscillator, effect, envelope and LFO types.

- Semi-modular, so lots and lots of routing options, both audio and cv.

- My personal playground for learning plugin and dsp development.

What it is NOT:

- Expect absolutely no innovation on the dsp/algorithm side. Math is not my strong-suit and lots of the more math-heavy stuff is implemented based on existing papers. See the github page for credits. Infernal's strength is mostly that it allows to combine all those existing algorithms through it's audio and cv routing matrices.

- Not a commercial product, just a one-man show. If it works for you, great! If it doesn't, contact me and we'll try to work out what's wrong. Expect to put in some effort yourself, too.

Supported hosts:

- Windows only, tested on Renoise, Bitwig, FL Studio, Cakewalk and REAPER (VST3), and REAPER, Bitwig (CLAP). Other hosts may or may not work correctly.


- 4 oscillators with multiple types (basic analog, mixed analog, DSF, noise, Karplus-Strong), and RM/AM/FM/PM.

- 6 per-voice DAHDSR envelopes with split attack/decay/release stages and slope control per split stage.

- 6 per-voice and 6 global LFO's of basic analog, random, and semi-free-form types.

- 10 per-voice effect modules with state variable filter, comb filter, and waveshaper.

- 10 global effect modules with state variable filter, comb filter, waveshaper, reverb, feedback delay, and multi-tap delay.

- Per-voice and global audio routing matrices with 15 routes.

- Per-voice and global cv routing matrices with 15 routes.

- 6 freely-assignable cv sources to be used through automation.

- Poly-and monophonic modes with portamento support.

- Regular, retrigger and multitriggered envelopes.

- Responds to MIDI pitchwheel, modwheel, channel pressure and channel volume.

- Resizable and themeable user interface.

Latest User Reviews

Average user rating of 3.75 from 4 reviews

Reviewed By hyborea [all]
December 27th, 2023
Version reviewed: 1.4 on Windows

First of all, thank you for sharing your work. I think the plugin has some functional design issues. I have done some tests by asking my sister, who knows nothing about plugins, to check if what I believed was just my own opinion or not. The organization of the elements is somewhat confusing. There are section titles that are confused with buttons because they are framed in the same way. Study how they solve these things in Surge xt dark or in Vaporizer. I would differentiate between sections by somewhat expanding the distances between them. I would use bold or different or larger fonts in the titles. You could also make the title area a different color. I think that if it gained legibility and looked aesthetically better organized it would gain a lot.

Response from sjoerdvankreel from sjoerdvankreel on January 2nd, 2024

Hey! Thanks for the rating and the feedback. InfernalSynth does indeed have some design issues. Truth be told, I won't be actively developing it any further "as is", apart from Mac support which i promised to do in the one-synth-challenge #174.

Instead i started a new project which is the same as infernal "in spirit", but with a more organized ui. Zero backwards compatibility of course but i aim for it to have a comparable feature set (not there yet) and better platform support (win/lin/mac). See below for screenshot. If you want, i can upload an early build somewhere.


Read Review

Reviewed By Warkauze [all]
July 10th, 2023
Version reviewed: 1.2 on Windows

Definitely not the easiest plugin to work with, however the amount of filters and waveshapers you can stack as well as the different oscillator modes make this one incredibly powerful. The new UI looks and flows much better then the original.

Response from sjoerdvankreel from sjoerdvankreel on July 11th, 2023

Every now and then I need a push like this to keep going. So, thanks.

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Reviewed By Germantownbassp [all]
April 10th, 2023
Version reviewed: 1.1.3 on Windows

I downloaded and installed. Used Cubase, but I trust the developer who said it ALSO works in Renoise, Reaper, Bitwig and FL. I am a neophyte, but I like it. I just have to learn more to use it better. Wish some of my KVRAudio pals would make a bank of presets, because it looks like this thing could do A LOT!!!!!!.

and ugly...? One person's ugly is the same person's cool. As a small child I forked out a ton of money for the big H.R. Giger book that was put out in the late 70s, early 80s. Is his art "ugly"?

I tried the "Versioned" and "Generic" versions. Even loaded both simultaneously, and no crashes.

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Reviewed By gwenmollo [all]
March 28th, 2023
Version reviewed: 1.0.1 on Windows

Can't even change the presets of initialise..

It's buggy and ugly..

Don't waste your time..

Response from sjoerdvankreel from sjoerdvankreel on March 31st, 2023

"Cant change the presets" what do you mean by that? Might just be a bug, if so, I'd like to know. What OS, what DAW?

Read Review

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