RTMS VAPolyTZFM is a new AUv3 polyphonic through-zero FM Synthesizer plugin for iOS and macOS (Apple Silicon only).
Through-zero FM became a topic this spring when Frap Tools from Italy introduced the Magnolia Synthesizer at Superbooth 2025. This is a synthesis technique often seen in complex oscillators, for example.
The benefit of this, unlike exponential or linear FM, is that TZFM stays in tune regardless of modulation depth. TZFM is not only a hardware thing. Ryo Togawa has just released VAPolyTZFM, a new polyphonic Synthesizer for iOS/macOS using through-zero FM.
RTMS VAPolyTZFM
VAPolyTZFM is a new 8-voice polyphonic Synthesizer featuring through-zero FM for macOS and iOS.
Since RTMS often releases multiple versions of its synths, it is worth noting that VAPolyTFZM is a mono-layer Synthesizer with two oscillators with continuously variable waveshape (triangle, sawtooth, square). Strange, no sine wave.
Each oscillator has classic controls, including tuning, fine, shape, and level. There’s a dedicated area for the TZFM function where you can precisely dial in the FM amount. Additionally, you can modulate the entire thing with an envelope and LFO.
According to RMTS, through-zero FM is capable of maintaining the pitch and thus enables it to deliver more musical results than other FM types.
Alongside the FM, you have pulse-width modulation, cross-mod, and hard sync options for the oscillators. Plus, you have a pink/white noise oscillator that can be mixed into the signal.
Then, it passes through a resonant low-pass filter with selectable 12dB and 24dB per octave slopes, and a high-pass filter with a 12dB per octave slope. Frequency modulation on the filter is possible via an ADSR envelope, LFO, and key follower.
On the modulation menu, you can find two ADSR envelopes with delay time and key follow parameters, and two multi-mode LFOs per layer. To refine your sounds, it also hosts a multi-FX processor with delay, chorus, flanger, EQ, compressor, and reverb.
Further, it has an analog-style sequencer, an arpeggiator, eight assignable macro controllers, and a built-in recorder.
AUv3 Support
RTMS VAPolyTZFM can be played traditionally with the keys on the interface or with a MIDI keyboard.
Like Ryo Togaware other synths, it’s also an AUv3 plugin on iOS and macOS (native Apple Silicon only. This allows you to use it in multiple instances in your DAW. Also worth mentioning is that it features Ableton Link, MIDI 2.0 and MIDI CC support, and more.
The app ships with 256 factory presets to get to know the app right away.
First Impression
At first glance, VAPolyTZFM is another beautiful, great-sounding synth from Ryo Togawa. However, I would like to see the developer release a flagship VAPoly synth in the future with all the features found in five other VAPoly apps. Otherwise, you slowly lose track of which RTMS synth is the best.
RTMS VAPolyTZFM is available now for an introductory price of $5,99 instead of $14,99. It runs as a standalone app and AUv3 plugin on macOS (native Apple Silicon) and iOS (iPhone/iPad).
More information here: Apple App Store
Sounds like shit. No wonder they have comments turned off on their videos.