Tutorials Audio

Upmixing Stereo to Surround and Immersive: What Halo Upmix States

By Infinite Creation · Professional · ~14 min

A 1960s mid-century comic book style editorial illustration showing a small mixing room where the sound from two front speakers fans out into a ring of seven speakers and a subwoofer, with one person at the console and another gesturing toward the speakers.

The Problem

An upmix spreads a stereo recording across more channels, such as the five full channels and one low-frequency channel of a 5.1 surround mix. Broadcasters ask for surround versions of archive and stereo-only material, and some immersive formats need a bed, the fixed channel layer under Dolby Atmos. This guide is for mixers and broadcast engineers who hold only a stereo master. It explains what NUGEN Audio states that Halo Upmix does, how its neural-network dialogue isolation is described, and the checks to make before an upmix goes into a delivery. We did not test any tool on this page. Each statement about a tool comes from the maker's own page as read on 8 October 2026, or from a trade source named in the Sources section.

Method

Check that an upmix is allowed

Some deliveries require the original multichannel mix and refuse an upmix, and others accept it with a label. The delivery specification and the buyer decide. Ask before you spend time. If the original stems exist, remixing from them gives the mixer control an upmix never has.

Pick the layout

NUGEN's page lists upmix to LCR, 3.1, 4.0, 4.1, 5.0, 5.1, 6.0, 6.1, 7.0 and 7.1. An optional 3D extension adds a Dolby Atmos bed at 7.1.2, Auro 3D at 7.1.4 and Ambisonic outputs. The page states the 3D extension currently supports Avid Pro Tools (AAX) and Steinberg Nuendo (VST3) on Windows and macOS.

Decide whether to extract dialogue to the centre channel

In surround, the centre channel carries most dialogue so it stays anchored to the picture. NUGEN's page lists switchable dialog extraction, which it describes as neural network powered dialog isolation. Try it with the switch on and off and listen for music or effects pulled into the centre, and for speech left in the sides.

Use exact mode when downmix compatibility matters

A surround programme is often folded down to stereo for other platforms. NUGEN states that because the upmix is coherent a downmix is high quality, and it offers an exact mode for cases where the relationship between original, upmix and downmix must be preserved, such as repurposing television. Check this yourself by folding down and comparing with the master.

Listen on calibrated speakers, then log it

Judge the upmix in a calibrated room, using the speaker calibration guide for setup. Listen for added width that changes the intent of the mix. Record the plug-in, layout and mode in the delivery notes and label the programme as upmixed where the specification asks.

What the Method Assumes

The stereo master, in the best quality available
The delivery specification, which says whether an upmix is accepted
A calibrated surround or immersive monitoring room
A way to fold the result back down to stereo and compare it with the master

Gotchas

Do not upmix a mix whose stereo image is the point, such as a deliberately narrow or phase-heavy sound design.
Keep the stereo master with the surround deliverable. Quality control sometimes compares the two.
An upmix does not make an Atmos mix. A bed upmix gives channels, not object placement.

Knowledge Base

Background and Detail

An upmix creates placement the original never had, so the question is always whether the result serves the programme.

What the page claims, and how far to trust it

NUGEN states that the algorithms produce a natural, coherent spatial upmix and add no artificial reverb, chorus or delays. Those are the maker's own descriptions. The page gives no measurement, no list of source material where the upmix fails, and no comparison with other upmixers. A search summary of a 2015 trade report, which we did not open, says the product launched at IBC 2015. If so, it is a long-standing tool and not a new one. Judge it on your own programme.

Loudness tools are a separate matter

NUGEN also sells loudness metering and correction tools used for delivery compliance. We did not check those pages, and they are not described here as AI tools. The broadcast loudness guide covers the measurement side.

Where This Fits

An upmix is a mix decision made without the original tracks, and Mixing a Full Song covers the balance and panning choices it replaces.

FAQ

Q: Does Halo Upmix run in Pro Tools?
A: The page lists AAX, VST3, AU and AudioSuite in 64-bit, and says the 3D extension supports Pro Tools (AAX) and Nuendo (VST3). It does not say which versions of those programs.

Q: Is the dialogue isolation always on?
A: The page lists it as switchable.

Q: Is an upmix the same as a remix?
A: No. A remix rebuilds the balance from the separate tracks. An upmix infers placement from a stereo file.

Vocabulary

Upmix Converting audio to more channels than it was recorded with, such as stereo to 5.1. The software infers where sounds belong, because the original holds no information about it.

Downmix Folding a multichannel mix down to fewer channels, such as 5.1 to stereo. A poor downmix cancels sounds or shifts the balance, so engineers check it against the original.

Bed The fixed set of channels under a Dolby Atmos mix, usually 7.1.2 or 9.1.2, which carries the ambience and main elements. Objects, which move independently, sit on top of it.

Centre channel The speaker directly in front, behind the screen. In surround it carries most dialogue so voices stay tied to the picture wherever the viewer sits.

Sources

NUGEN's own page was read on 8 October 2026. We tested nothing. Checked 8 October 2026.

NUGEN Audio, Halo Upmix. States the supported layouts, switchable neural network powered dialog isolation, an exact mode for downmix compatibility, an optional 3D extension for Atmos bed, Auro 3D and Ambisonic output, plug-in formats, and that the 3D extension supports Pro Tools (AAX) and Nuendo (VST3).
Post Magazine, NUGEN Audio release Halo Upmix (2015). Seen only as a search result about the product launch at IBC 2015. Not opened or read.

No page we read states a measured result or a delivery rule on upmixes. NUGEN's loudness products were not checked. No source we read mentioned a change of NUGEN's ownership.