RSJB Tonic is a multi-layer, 3-oscillator, multi-engine Synthesizer plugin for iOS and macOS: update 2.0 adds user waveables, vector synthesis, and more
In early July, I reported on the Tonic multi-engine Synthesizer for iOS and macOS from the new Brazilian company RSJB. The creator confirmed to me that the app was developed with AI because it was only through that he could realize his vision.
It’s better to communicate clearly than to cover it up. AI tools not only allow for faster plugin development, but they also enable updates to the high-speed train. This is evident here.
Update 2.0
After just 11 days on the market, there’s already a major update 2.0 for the Tonic Synthesizer, something that previously took weeks or even months to develop.
Update 2.0 is a free update that adds plenty of new features to it. I wrote in the original article that both an arpeggiator and a sequencer were missing. These have now been added.
The new arpeggiator offers 12 modes (up, down, zigzag, chords, gate…) with up to four octaves and programmable swing, ratcheting, ties, accents, probability, and ghost notes.
It’s also possible to use it as a sequencer with the step editor and rhythm masks. You can also capture notes. Alternatively, you can import MIDI files. Each preset has eight ARP scenes, and a factory of 20 ready-made arpeggios is built-in.
The Tonic 2.0 also improves upon its synthesis capabilities. The wavetable engine now turns any sound into a wavetable with up to 128 frames. You can import an audio file or record with the mic.
Once done, it visualizes it in 3D, with the option to drag, rotate, and add motion. This makes the wavetable engine more versatile than before.
Alongside the new, more advanced wavetable engine, RSJB also added vector synthesis to the oscillators. With an XY pad, you can blend through all three oscillators in real time. This can be done manually, or via automation of an LFO, an envelope, or by drawing a motion path into it.
Then, in the multi-FX section, you can find a new 5-band EQ with custom frequencies. You can access it by long-pressing.
Further, it comes with various engine improvements, including updated super saw/string model/FM engines, redesigned scenes (A-F), a re-assignable mod-wheel, temp tempo, and more.
It’s positive to see that the developer has added new features to Tonic, such as the arpeggiator/sequencer.
However, I still think the plugin looks too generic, and the price is far too high. It’s one of the most expensive iOS synths on the App Store. For the price, I have very high expectations.
The RSJB Tonic 2.0 update is available now as a free update for existing users. The app/AUv3 plugin is out now for $34,99 and runs on iOS and macOS.
More information here: RSJB / App Store
Article from July 10, 2026
The impact of AI and vibe coding is currently evident in the Apple App Store. New synthesizers from new developers are released almost daily, whereas previously there were only 3-4 per month. The flooding is underway. Here’s another synth from that genre.
Rubens Felicio aka RSJB, a new app developer, has released Tonic, a feature-rich, multi-layer Synthesizer plugin.
RSJB Tonic
Tonic is a new multi-layer, multi-engine synthesizer for iOS, macOS, and even Android. For Android, there’s only a standalone version because Android doesn’t support plugins.
Looking at the developer’s portfolio, he released three apps within a month. A glance at the app and website also reveals that generic designs were used. So I’m sure RSJB coded/prompted the Tonic synth with AI.
The feature set is very large. I’ve rarely seen such a comprehensive synth. Prompt as much as possible could be the motto.
Tonic has three independent layers, with a per-layer keyboard split option and mute and solo options. Each layer has its own oscillators, filter, envelope, and modulation.
8 different sound engines are available: string, modal, classic VA, wind, bowed, wavetable, SF2 (SoundFont), and 6-OP DX7 FM. I think they use the open-source Mutable Instruments Plaits algorithms heavily here, because the names remind me of them.
Each engine offers a wide range of adjustable parameters. Plus, there is a sub-oscillator and noise generator per layer.
The filter also offers a wide range of different types: 4-pole ladder, silk SVF, snap, acid, scrm, 2-pole multimode, LPG, and OTA ladder. They are fully adjustable with classic cutoff, resonance, and drive controls.
Modulation & Effects
The modulation works at the layer level, so each layer has its own envelopes and multiwave LFOs. Alongside this, you have envelope followers, pitch bend, and mod wheel as modulation sources.
To refine your sounds, there is a global multi-FX engine with various choruses, ping-pong/tempo-synced delay, FDN-based reverb, 5-band EQ, compressor, flanger, and bit-crusher. Each effect is fully adjustable and independently usable.
And no, there isn’t an arpeggiator or sequencer built-in. Sounds can be saved in the Tonic presets browser, where you also find some factory presets by RSJB.
First Impression
Based on its features alone, Tonic looks like a powerful multi-layer Synthesizer. However, in terms of design and workflow, the synth feels very generic, just as you’d expect from a vibe- or AI-coded synth.
What many prompters forget is that a crucial aspect of an app, especially in music production, is the user interface—how user-friendly and inspiring it is. Unfortunately, AI can’t do that yet. Only professional designers are good at that.
Packing together a huge number of Synthesizer features isn’t rocket science these days. But making it all inviting and appealing, so it doesn’t look cobbled together, is something else entirely.
At the current price of $34.99, absolutely not. $3.49 maybe, but no more. Especially since updates and the future depend on an AI agent.
RSJB Tonic is available now for $34,99. It runs as a standalone app and AUv3 plugin for iOS and macOS (native Apple Silicon).
I have no problems for AI generated software but,$34,99 for AI generated plugin..really..?!
No thanks.
For me, it doesn’t really matter where the graphics were generated.
The synth is highly comprehensive, featuring various forms of synthesis and fantastic filters, along with intuitive controls that are very practical to operate. Everything is mappable.
It comes with a wonderful effects rack, and most importantly: it consumes very little processing power. The value for money is immense!
It’s the best synth I’ve ever invested in for my iPad, and now, my definitive synth!
It’s actually quite cheap for what it offers. I would need a whole stack of other synth apps to get anything close to what Tonic offers, and even then, without the same integration, practicality, and efficient processing management.
it’s one of the most expensive synth apps on the App Store, that’s a fact 😉