UpM1xer

Why upmixing is harder than it sounds

The most common mistake in spatial mixing has a name: "big mono." It's the instinct to take a source and route it to more speakers — as if coverage equals space. It doesn't. Spatiality is created by difference — the subtle distinctions between what each ear receives from distinct locations. Spreading the same sound around the room fools no one.

A solution for this is to make your source tracks behave differently in each location — adding tape saturation, introducing reverb into the rears to envelop the listener, and so on. But this creates a new problem: every modification pulls your spatial mix further from the original stereo, making it harder to deliver a version that's faithful to the original stereo mix.

That's exactly the problem UpM1xer is built to solve.

UpM1xer deconstructs your source signal at a spectral level and intelligently redistributes it across the room, drawing on decades of psychoacoustic research to create genuine envelopment — while preserving the intent of the original mix. Switch on Exact Mode and UpM1xer guarantees stereo fold-down identity to within -120 dBFS, so your spatial and stereo deliverables are mathematically consistent, this also means that UpM1xer can be used for post-production tasks.

6 Engines. One for every situation.

UpM1xer offers six distinct spatial processing engines — Subtle, Natural, Wide, Deep, Elevated and Expansive — each defining a different spatial geometry. Whether you need the barest hint of width or full 360° envelopment, there's an engine to match. All six go far beyond simple EQ-to-speaker routing; the underlying algorithms are grounded in psychoacoustic principles and have been tuned specifically for music production.

Stem Profiles. Built for how music is actually made.

UpM1xer is designed to work with stems. Six profiles — Full Mix, Drums, Vocals, Harmonic, Pads and Bass — optimize spectral analysis and channel routing for each source type, giving you results that are tailored to the material rather than generic.

Transient control. Because upmixed drums should still hit hard.

Spatial processing can rob drums of their punch. UpM1xer's Transient Sensitivity control lets you dial in exactly how aggressively the plugin detects and handles transient content — keeping your kick tight and your snare cutting through in your surround mixes and Dolby Atmos / Apple Spatial renders.

Additional features

Include two diffusion modes, LFE sub-harmonic synthesis, EQ shelving for speaker pairs, Exact Downmix mode and automatic mono detection. With full AU / VST3 support on Apple Silicon (AAX coming soon)

Built for music. Priced for music producers.

Until now, upmixer plugins have been tools built for post-production, with price tags to match. UpM1xer brings professional-grade upmixing to music production at a competitive price — without compromising on the features that matter. It handles post-production workflows too, but music is the priority.