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The opx 4 Black Friday deal is 77% off, $34, with the offer ending Nov 26, 2026, on AIR Music Technology's four-operator FM synth plugin.
OPx-4 is a four-operator FM synthesizer built around a 4x4 FM matrix, with tone shaping and filtering inside it. The maker says the control layout is easy to follow, even if FM has tripped you up before.
This OPx-4 VST gives you wave shaping, a dual-mode filter path and a 32-slot modulation matrix in one instrument.
FM synthesis takes classic oscillator waveforms and modulates them until they turn into something new. The maker says OPx-4's layout lets you experiment by turning knobs, without needing to understand the maths underneath.
All four operators can be adjusted directly on the display, covering pulse width, formant, plus filtering and shaping of the FM signal. Each also gets its own ADSR and FM oscillator envelope controls.
The maker points to classic electric pianos, 80s FM synth sounds and strange FM sound effects. It also describes deep, evolving patches with a strong attack, morphing or filter movement.
OPx-4 pairs a four-operator FM engine, which offers wave looping and sample offset along with several filters, with a dual-mode filter path covering 23 filter types. Modulation comes from six envelopes that can loop in sync with the host tempo, plus a pair of LFOs and a pair of ramps, all routed through a 32-slot FM matrix. Eight macro knobs can be assigned freely, several preset banks are included, and the effects section holds three insert slots and two global slots. They draw on 27 included AIR effect plugins, covering reverb, delay, distortion and modulation. The built-in engine also lists compression, EQ, amp sims and lo-fi effects.
The maker mentions shimmers, dark echoes and washed-out DX-style electric pianos as things the effects can build.
One purchase unlocks the plugin on three devices, including PC, Mac and standalone on MPC and FORCE.
On PC you need Windows 10 to 11 and a minimum dual-core 2.5GHz processor. On Mac you need macOS 10.15.7 up to macOS 12.4 Monterey, Apple Silicon native, with a Core Duo processor. A Core i5 or i7 is recommended.
The minimum is 4GB of RAM, with 8GB or more recommended. You also need 2GB of free disk space, or 20GB if you want all the content. Download and authorization need internet access.
Yes. The OPx-4 Black Friday deal is 77% off, bringing the price to $34, and the offer ends Nov 26, 2026. It covers AIR Music Technology's four-operator FM synth plugin in its PC, Mac and standalone versions.
Yes, OPx-4 comes as a VST plugin in 32 and 64 bit, qualified for Ableton Live, Cubase, VIP and MPC. It also ships as AU for Logic Pro X, AAX for Pro Tools 11+, and RTAS for 32-bit Pro Tools.
You get a four-operator FM engine with a 32-slot modulation matrix, 23 filter types, six envelopes, two LFOs, two ramps and eight macro knobs. Three insert FX and two global FX draw on 27 included AIR effect plugins, plus multiple preset banks.
PC needs Windows 10 to 11 and a dual-core 2.5GHz processor. Mac needs macOS 10.15.7 to 12.4 Monterey, with Apple Silicon native support. Minimum RAM is 4GB, with 8GB recommended. You need 2GB of free disk space and internet access for download and authorization.
Prices and end dates are checked at publishing time and can change, so confirm them at the store before you buy.