Max1mus Audio UpM1xer v1.1.1 [WiN]

Stereo to surround upmixing, done right
Most upmixer plugins were designed for broadcast and post-production - converting legacy stereo content into surround for TV, streaming, and film. They typically work by extracting the phantom center channel and diffusing the remaining ambient signal to the rear speakers.

That approach falls apart with music. Stereo music mixes are dense, layered, and dynamic. Simple channel extraction creates the "big mono" problem - where everything sounds like it's coming from the front, with vague reverb tails in the surrounds. Not immersive. Just wider.

UpM1xer takes a different approach. It deconstructs your source signal at the spectral level and intelligently redistributes energy across the surround field. Instead of simple panning and delay tricks, UpM1xer analyzes the frequency content, transient behavior, and stereo image of your audio in real time - then places elements where they naturally belong in a 3D space.

The result is a surround upmix that sounds intentional, not algorithmic. Your kick stays anchored in the center. Pads and textures wrap around the listener. Reverb tails bloom into the height channels. And it all folds back down to stereo perfectly.

Six upmixing engines for every source
Every source needs a different touch. UpM1xer includes six processing engines - Subtle, Natural, Wide, Deep, Elevated, and Expansive - each tuned for a different level of spatial spread and immersion. Pair these with six stem-aware profiles (Full Mix, Drums, Vocals, Harmonic, Pads, Bass) to match the processing to your source material.

Running a vocal bus through a 7.1.4 Atmos bed? Use the Vocals profile with the Subtle engine. Processing a synth pad for height channels? Try Pads with Expansive. The combination of engine and profile gives you 36 starting points before you touch a single parameter. No other upmixer plugin gives you this level of control over how your stereo source is distributed across surround channels.

Built for Dolby Atmos music production
UpM1xer supports surround formats from quad (4.0) up to 7.1.4, including all the Dolby Atmos bed track formats used in music production:

5.1 - Standard surround

5.1.2 - Atmos bed with top channels

7.1 - Extended surround

7.1.2 - Atmos bed (Logic Pro, Pro Tools)

7.1.4 - Full Atmos bed with four height channels

Whether you're working in 5.1 or full 7.1.4, UpM1xer is the upmixer plugin that handles every Atmos bed format. Use Exact Downmix mode for 100% ITU-compliant downmix compatibility - verify that your surround mix folds back to stereo without phase issues or level changes.

Intuitive controls, professional results
UpM1xer is an upmixer plugin that puts you in control without overwhelming you.

Easy Mode - Simplified controls for quick results. Pick an engine, pick a profile, done.

Transient Control - Preserve or soften transient impact in the surround field

Dispersion Modes - Two configurable modes for controlling how energy spreads across channels

LFE Sub-Harmonic Generator - Add weight to the LFE channel without muddying the main mix

4-Way A/B/C/D Comparison - Compare four different settings instantly

Fully Automatable - Most parameters available for DAW automation

Resizable GUI - Light and dark modes

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