OPx-4 is a groundbreaking FM synthesizer with four operators, advanced sound editing, and an easy-to-understand control scheme. In addition, the system has one of the most advanced FM engines ever created, with a 4×4 FM matrix that includes tone shaping and filtering, and a 32-slot matrix for modulating your FM tones.
Groundbreaking FM Synthesizer Engine
With flexible wave shaping, a dual-mode filter path with 23 different filter types, six envelopes with tempo-synced loops, two LFOs and two ramps, the OPx-4 will become your favorite FM synth. It includes three insert effects and two global effects for use with AIR’s 27 included effect plug-ins, such as reverb, delay, distortion, modulation effects and more.
FM synthesis works by taking classic oscillator waveforms and modulating them until they sound like something completely new. If you’ve ever experimented with FM synthesis, you know that it can be difficult to figure out how to create great sounds. The OPx-4’s simple layout and easy-to-use controls make it easy to experiment with FM features without requiring a deep understanding of how it works behind the scenes. The easy-to-understand control layout makes experimenting as simple as turning knobs until it sounds great!
Four Operators, Two Filters, Thirty-Two Modulation Sources, ONE Great Sound
Using four FM operators and an FM operator matrix, you can create virtually any FM sound you’ve ever heard, or even ones you’ve never heard before! You can adjust the values of each operator using dedicated on-screen controls for pulse width, formant, FM filtering, and FM shaping, as well as dedicated ADSR and FM oscillator envelope controls.
Built-in effects engine to style your sounds
The OPx-4 includes a variety of effects such as EQ, amp sims, reverb, delay and modulation. Create shiny shimmers, dark haunting echoes or spacey DX-style fuzzy electric pianos with the advanced effects engine built right into the instrument.
Unlock these sounds in Akai MPC/FORCE for FREE
Buy this plugin and you will be able to unlock it in your Akai Professional MPC/FORCE Standalone hardware, as well as use it in your favorite DAW. Seamlessly transfer productions from standalone hardware to your DAW with the same great sounds.
New features
- Optimized Apple Silicon support — Installers and all plug-in components now run natively on ARM-based Macs.
- Improved DAW compatibility — Improved stability and performance with the latest versions of major DAWs.
- New license deactivation option — Users can now deactivate licenses directly from the menu.
- Mono FX versions — Effects now support Mono -> Mono processing.
- Preset change indicator — The preset field now visually signals when a parameter has changed.
- Bug fixes and improvements
- General bug fixes across multiple plugins.
- UI and activation improvements for a smoother workflow.
- More robust preset handling – ensures the correct preset name is loaded with project files.

- Download AIR Music Technology – OPx-4 1.2.1.14 STANDALONE, VSTi, VSTi3, AAX x64 [06.2025](TCD)
- Original Publisher: AIR Music Technology
- Version: 1.2.1.14
- Format: VSTi, VSTi3, AAX, Standalone
- Category: Virtual instruments and synthesizers
- Require: Windows 10+
- License type: Full
- Download Size: 37.4 MB