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OPx-4 OPx-4 OPx-4 OPx-4 OPx-4 OPx-4
OPx-4 by AIR Music Technology is a Virtual Instrument Audio Plugin and a Software Application for macOS and Windows. It functions as a VST Plugin, an Audio Units Plugin, a VST 3 Plugin, an AAX Plugin and a Standalone Application.
Windows 10 (21H2) - Windows 11 (21H2
macOS 10.15.7 Catalina - macOS 12.4 Monterey (M1 compatible - check Specific MPC Models for Driver Support)
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OPx-4 gives you deep, compelling FM synthesis that is easy to dial in:

  • Four operator FM synth engine with wave looping, sample offset, and multiple filters.
  • Make deep, evolving sounds with a strong attack, morphing, or filter movement.
  • Create digital tones like classic EPs, 80s FM synth sounds, or strange FM sound effects.
  • Built-in effects with compression, EQ, delay, reverb, lo-fi effects, and more.
  • Eight assignable macro knobs for easy-to-control FM synth effects.
  • A 32-slot FM modulation matrix for the ultimate in sound design potential.
  • Multiple preset banks give you easy access to great FM sounds.
  • Purchase unlocks plug-in on three devices including PC, MAC (VST, AU, AAX) and Standalone (MPC & FORCE).


Hello Operator, Get me OPx-4!

OPx-4 is a groundbreaking four operator FM synthesizer with advanced sound editing and an easy-to-understand control layout. In addition, the system has one of the most profound FM engines ever built with a 4x4 FM matrix that includes tone shaping and filtering and a 32-slot matrix for modulating your FM tones.


Features expansive presets crafted by the AIR engineering team.


A Groundbreaking FM Synth Engine.

With its flexible wave shaping, dual-mode filter path with 23 different filter types, six envelopes with tempo-synced looping, two LFOs, and two ramps, the OPx-4 will become your go-to FM synth. It includes three insert FX and two global FX for use with 27 included AIR effect plugins, such as reverb, delay, distortion, modulation effects, and more.

Leave Your Sound Design Ph.D. at the Door. OPx-4 Makes FM Synthesis Easy.

FM synthesis works by taking classic oscillator waveforms and modulating them until they sound like something brand new. If you've ever experimented with FM synthesis, you know it can be complicated to understand how to make great sounds. OPx-4's simple layout and easy controls make it a breeze to experiment with FM functions without needing a deep understanding of how it works behind the scenes. An easy-to-understand control scheme makes experimenting as easy as turning knobs until it sounds great.

Four Operators, Two Filters, Thirty-Two Mod Sources, ONE Great Sound

Using four FM operators and an FM operator matrix, you can craft almost any FM sound you've ever heard—or even those you haven't heard of yet! You can adjust the values of each operator using specific on-screen controls for pulse width, formant, FM filtering, and FM shaping, as well as specific ADSR and FM oscillator envelope controls.

Built-In Effects Engine to Stylize your sounds

OPx-4 includes multiple effects like EQ, amp sims, reverb, delay, and modulation. Create brilliant shimmers, dark haunting echoes, or spacey washed-out DX-style electric pianos with a cutting-edge effects engine built right into the instrument.

Unlock these sounds in Akai MPC/FORCE for FREE

Purchase this plugin and you'll get the ability to unlock it within your Akai Professional MPC / FORCE Standalone hardware as well as using within your favorite DAW. Seamlessly move productions from standalone hardware to your DAW with the same great sounds.

This instrument is available in VST, AU, and AAX format as well as offering full support for MPC standalone and desktop systems running version 2.11 (or later). FORCE users will need version 3.2 or later. Click below to download and install the 10 day trial of the OPx-4 desktop VST, AU, or AAX version of this plugin.

{See video at top of page}


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