Fluctus Is A FREE FM Synthesizer In CLAP Plugin Format For Windows


Nakst releases Fluctus, a freeware 3-operator synthesizer available in CLAP plugin format for compatible digital audio workstations on Windows. The instrument is also available for FL Studio.

Fluctus features three FM operators arranged in a loop so that each modulates the next one. As a result, the signal can be modulated quite heavily, opening the potential for exciting FM sounds. Each operator has ADSR sliders along with brightness and detunes controls. There is also a set of master controls.

The operator layout in Fluctus visually displays the synthesis path and makes it relatively simple to understand for those new to FM synthesizers. The waveform preview display is also helpful when creating sounds from scratch.

Fluctus also features numerous effects that can add interest and depth to the generated sounds. At the bottom of the interface, users can apply hard or soft saturation, an LP/HP filter, ping-pong delay, and a phaser. This virtual synth also supports up to 2x oversampling.

Speaking of the interface, Fluctus is designed with ease of use in mind. The colorful layout is clear and concise and can be resized from 100% to 200% if desired.

A basic understanding of FM synthesis can help elevate your music production and sound design skills to the next level. While the 60 presets available in Fluctus can be a great starting point, creating your patches can add authenticity to your sound.

Fluctus is entirely FREE and requires no email sign-up or account creation. Follow the link to the Nakst website and click the download button to get your free copy of the instrument.

The software is compatible with 32-bit and 64-bit Windows-based plugin hosts that are compatible with the CLAP plugin format. It is also available in the native FL Studio format.

CLAP is a plugin format initially designed as open-source software in 2013. Recently, big names such as U-He and Bitwig have backed the project and are beta-testing their software in this format.

Have you used the CLAP plugin format yet? What are your thoughts on it? We’re looking forward to reading your thoughts in the comments section below.

Download: Fluctus


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    • Usually skin lesions, and a burning sensation when you go pee. Ask your doctor.
      Sorry, had to do it. Haven’t yet the ‘pleasure’ to test anything CLAP, maybe this one is a good candidate.

        • I don’t mind the name, on a personal level. I find it funny, even. But as a commercial name, aimed at a larger crowd… heh.
          CLAP has a legitimate use in english, and maybe a lot of other languages for the handclap. But indeed, in english, it has also another meaning. Afterall, some big companies spent many monies in research of a name and got burned in the past. At least, they’re owning it. :D

          • Tomislav Zlatic


            I actually made a similar *thing* by accident ages ago when I released a free plugin called Clap Machine on 99Sounds. It was indeed just a rompler for handclap sounds, and I had no idea about the other meaning of the word clap, let alone the slang meaning of “clap machine.” So, yeah, I quickly learned about it after reading the comments. :) It was too late to change the plugin name at that point, though, so I just left it as-is.

        • It stands for CLever Audio Plugin. So no, the name is fitting. The problem you have is with the ACRONYM used for the plugin. Which also, fits it just fine.

  1. I am not sure if I would call this freeware. The page is rather “aggressive” about wanting donations, and it is not easy to understand how one can download this free without paying ?
    Beyond the novelty of being CLAP, a 3 operator FM synth, with filter, delay and phaser, can hardly match top of the line freeware synths like Surge

    • If looking for an FM synth, at this time I think FM8 at $12.5 is a better deal, than paying the $10 donation suggested by Fluctus

    • I don’t think “Name your own price” qualifies as aggressive. Nor does the “No, take me to the downloads”. Not disagreeing with the FM8 being a good deal, but you could argue that the software is getting old, basically not updated anymore and clearly made NI a ton of monies already. So selling it for anything is pure benefits at this point. Still a nice synth and a pretty good deal, mind you, no question about that.

  2. Epic Stock Media celebrate 10 million downloads, offering a free SFX pack of 800 samples suitable for game and film scoring:

  3. Having spent an hour on it, I can say it’s a cute little FM synth. It goes beyond the simple 2op scheme, which is nice for a bit more complexity. It only has sine? Yes and no, the Bright knob skews the sine to some kind of non-spiked saw, sorta. The 3 preview panels themselves are great for learning what FM actually does, they even respond to the ADSRs -and- modulations, even the detuning, so you really get to see what the operators are doing in realtime. As an FM learning tool, this is great. And fun. It’s almost a shame they’re a bit tiny compared to the rest of the UI and that you don’t have a Final waveform view. Knobs are smooth and free of zipper noise, so it’s nice to twist them while holding a droney chord.

    • Mmm, actually I’m wrong, there are zipper noises. I believe they were masked by the use of a low-pass filter, they are not that bad, but they’re there. Sorry. :/

  4. I am unfamiliar with NAKST, which always makes me uneasy. I ahte installing software from new/unproven companies. The product both LOOKS and SOUNDS great, but VirusTotal has come back with 4 positives for malicious behavior (INCLUDING gOOGLES OWN cLOUD dETETCTION). Can anyone confirm that these are just false positives and that the plugin is not malicious? Has anyone noticed anything weird?

  5. I installed this plugin and my computer exploded, it’s the second hard drive I lose because of this instrument! Someone should sue these people now!
    Sarcasm aside, this is the first time I test it using a DAW (Reaper) since now it supports clap natively. Firstly, I don’t mind if this new architecture is called clap or spank or whatever, as long as it works for me, which is the case now. FM synths are one of my must-have and my favorite synthesizers, and I’m amazed that it’s accessible with screen readers (although I had to deal while selecting presets). I still need to test it using my midi controller, but the controls seem to work as intended.
    I look forward to seeing what happens with this plugin in the future!

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