IMFMSynth is a new FM Synthesizer plugin by Kaito Sato that marries eight FM operators with wavetables and no fixed algorithms: update 1.1 out now
This week, I reported on IMFMSynth for the first time, an 8-operator FM Synthesizer that can also use wavetables as waveforms. It has already been on the market in beta for several weeks, and the developer promised a major update soon.
Scroll down for all the details. Kaito Sato, the developer, has now published update 1.1 with some great additions.
Update 1.1
Version 1.1 is now available as a free download for all users. The soft synth is still in beta, so the low introductory price remains in effect.
In the original article, I described it as a “zero-fixed-algorithm” FM synth because you can build your own algorithms using a matrix. That is no longer correct.
IMFMSynth 1.1 introduces 32 six-operator algorithms that you can choose with the ALGO button. They are numbered as on the Yamaha DX7, and you can also build the points envelopes from R1-R4/L1-L4 values.
So, for anyone who prefers to use it as a classic DX7, this is now easily possible. You can also switch any operator between ratio and fixed, with the whole-number and fractional parts of the frequency edited separately.
Also a welcome addition is the new per-operator hard sync and ring modulation option where the sync ratio is available as a modulation target. On top of that, there is now audio-rate wavetable scanning and a modulatable FM amount control from 0 to 200%.
The reorderable effects, originally announced as a future feature in the article, are now part of the engine. The optional 8-bit stage is also now fully customizable with mix, bit depth, and sample-rate reduction controls, all available as modulation targets.
Modulation also got a boost in update 1.1: modulator rates can go down to 0, modulators can modulate each other, and noise can be seeded to repeat the same pattern on every note-on.
Other neat additions are:
- CLAP host modulation
- MTS-ESP microtuning
- WAV export and wavetable import with automatic pitch detection
- workflow improvements (undo/redo buttons, interface language selection, UI scaling, and more)
A nice first major update for the 8-operator FM Synthesizer, with many lovely additions.
Version 1.1 is now available as a free update for existing users. IMFMSynth by Kaito Sato is available as an introductory/early access version for $19 instead of $49. It runs as a VST3, AU, and CLAP plugin on macOS (native Apple Silicon + Intel) and Windows.
More information here: Kaito Sato
Article from September 22, 2026
FM synthesizers are usually associated with sine waves and six operators—the classic Yamaha DX-7 mindset. However, synths like the TX81Z (1987) and many later models broke new ground, offering different waveforms and more operators to open up FM sound design.
Kaito Sato, a young Japanese developer, also embraces this FM mindset with IMFMSynth. It’s an FM synth that doesn’t try to be just another DX-7 clone.
Usable in 10 languages
IMFMSynth is a new FM Synthesizer plugin for macOS and Windows. Don’t worry, it’s not the hundredth vibe-coded DX-7 emulation plugin. We don’t need any more of those, since Dexed has been around for a long time and covers all the DX-7 basics at a high level for free.
I don’t know if AI played a role here, but in a post on the site, Kaito writes about AI from a developer’s perspective. I suspect—though I can’t say for sure—that AI was used here to speed up tasks, for example.
The user interface has a special touch with fonts that reminds me a bit of retro gaming. I don’t know why, but it has that kind of charm. It also has other lovely little extras, including support for ten languages. I only know this from Mok Miniraze, which supports Klingon.
The signal path display is also exemplary; when you select a virtual cable, it lights up to highlight the connection. These little details add something special to UIs. An Easter egg would have been the icing on the cake, but there isn’t one for now.
IMFMSynth
Kaito Sato, the developer, is taking a different approach with the IMFMSynth. At its core are eight operators you can wire freely.
A dedicated FM matrix gives you full control over your operator adventures. No fixed algorithms; you can modulate any operator with any other. This breaks through the 32-algorithm wall typically found in DX-7-inspired synths.
The advantage is that you aren’t limited to the 32 algorithms; instead, you can explore new connections, giving you more ways to experiment with the FM operators.
For instance, you can also create non-FM sounds by routing the operators to the filter stage. Every connection carries its own depth and phase, plus an operator can feed back into itself.
The synth also takes an unconventional but welcome approach to waveforms. Instead of just classic sine waves, you can load noise and wavetables into the operator. You can scan them like in Xfer Serum. Talking of this: you can load Serum- and Vital-style wavetables into it.
Using all kinds of wavetables instead of simple sine waves takes it to another level. Each operator also has a dedicated amount level, detune in cents, per-operator feedback amount, and options for fixed frequency and waveform invert.
Deep FM Sound Design
Each operator also has an envelope. ADSR, yes, but it goes further than that. Beyond that, you can turn the simple ADSR into a multi-segment envelope with as many points as you like. Plus, you can set a curve per segment and custom sustain and loop points.
If that’s too deep, it also has a DX-7 bank import function that gives you instantly playable, editable sounds.
This FM synth has filters, too—not just one, but three from the sophisticated shelf. IMFMSynth has three filter stages; each has its own type, ranging from classics like low pass or high pass to more unique ones like comb filtering, ring mod, and allpass.
Each filter is fully controllable with various features like cutoff, resonance, and slope, plus key tracking, drive, and selectable character for extra color and bite.
Just like the operators, the filter also has its own matrix where you can define the signal path yourself. This allows you to decide which operator goes into the first filter, which into the second, and so on. Total flexibility.
This total flexibility is also visually apparent from the very first page. Operators, filters, and the output share one screen, and you connect them by dragging an arrow from an output port to an input port.
Alongside the eight powerful envelopes, it also houses six multi-wave LFOs with sample-and-hold, tempo-sync, fade-in, and more. Drag-and-drop is not supported here. However, the modifiable areas are highlighted in blue, which is very intuitive.
To refine your sounds, IMFMSynth also features a multi-FX processor with various algorithms: Drive, chorus, delay, and reverb. They all have dedicated controls. There is also an 8-bit output mode and output protection with soft clipping
A major update is in the making, bringing a global FM amount knob, reordable effects, and more. Currently, the plugin only has 30 presets, but I hope that changes in the future. If you want to learn more about Kaito Sato, Sonicstate has an excellent interview.
A classic arpeggiator or fun sequencer is currently missing, but we may see them in later updates.
IMFMSynth First Impression
Kaito Sato offers here an exciting FM synth with a refreshingly modern set that goes far beyond what a DX-7 emulation can do. Wavetables, plus free signal-path routing, are great to have, as they open the door to more flexible patch design.
For $19, you get a powerful 8-operator FM synth in beta. If you’re unsure, you can try out the synth in your browser for free.
IMFMSynth by Kaito Sato is available as an introductory/early access version for $19 instead of $49. It runs as a VST3, AU, and CLAP plugin on macOS (native Apple Silicon + Intel) and Windows.
More information here: Kaito Sato
Looks lovely and sounds great, must give it a try.