UHJ Decoding

UHJ Stereo is a technology from the 1970s which encodes a degree of spatial detail into a stereo signal. These plugins aim to recover it.

Plugins are included that can produce quad, or limited first order ambisonic B-Format for use with other decoder libraries.

UHJ Stereo contains an impressive degree of spatial information given that this information is hidden inside a stereo stream. However, its resolution is far lower than modern technologies such as O3A. These plugins are primarily aimed at listeners with existing UHJ Stereo music libraries.

These are VST2 or AAX plugins for macOS (10.14 to 13.5) or Windows (10 or 11, 64bit Intel). They can be hosted in some Digital Audio Workstations (DAWs) that can handle tracks with sufficiently high channel counts. Options include Reaper, Pro Tools (Ultimate or Studio), Pyramix and Max/MSP. Not all plugins are supported in AAX.

We use some free software, data and artwork in these products. Before purchase, please check the technical requirements and license agreement. Prices include VAT where applicable. EU VAT is normally charged at your local rate using the MOSS VAT system. By beginning the payment process you agree to be bound by our terms and conditions.

Classic Quad Decoding

The UHJ Decoder - Quad decodes UHJ Stereo to a four channel Quad output using a recreation of a historical decoder design by Michael Gerzon.

UHJ Decoder - Quad

Converting to First Order Ambisonics

Alternatively the UHJ Decoder - O1A plugin recovers a first order (O1A) ambisonic stream, although with no height information, and reduced horizontal resolution.

UHJ Decoder - O1A

The recovered first order stream can then be processed further, or decoded in other ways.

Finding UHJ Stereo

A number of commercial releases have been made using UHJ, notably from Nimbus Records.

UHJ Stereo can also be produced from O1A or O3A using plugins, although we don't particularly recommend UHJ as a modern delivery mechanism.

Decoders

UHJ Decoder - O1A

UHJ Decoder - O1A

I/O: 2 in, 4 out

This plugin extracts first order B-Format from a UHJ Stereo input.

UHJ Decoder - Quad

UHJ Decoder - Quad

I/O: 2 in, 4 out

This plugin renders four-channel surround for a quad speaker array from a UHJ Stereo input, using an algorithm based on a design by Michael Gerzon.

Technical Requirements

Please check everything is okay here before purchasing software.

Operating System

Supported versions of Microsoft Windows are 10 or 11, 64bit Intel.

Supported versions of Apple macOS are 10.14 to 13.5, 64bit Intel or Apple Silicon.

VST Host

The VST plugins require a VST 2 host with shell plugin support.

These plugins do not work with all VST 2 hosts. They are multichannel plugins and so will not work on VST hosts that only handle stereo. Also note that not all VST 2 hosts can use shell plugins. In particular, at the time of writing shell plugins are not supported in Nuendo 8.

AAX Host

The AAX plugins require Pro Tools Ultimate or Studio.

PC Hardware

Please check your PC meets the following requirements:

  • Intel Pentium D CPU or better, or Apple Silicon.
  • 200MB of free disk space.

Internet Connection Required

This software requires an Internet Connection for license activation and verification.

Successful license verification isn't required every time you use the software, but it is needed during installation and needs to succeed once every couple of weeks to keep the license fresh.

The license can be "revoked" to remove it from one machine so it can be moved on to another. You should also do this if you're updating your system in case the machine appears to have changed identity.

Permissions

You'll need administrator permissions while installing on Windows. The software probably won't install properly using a "restricted" account.

Internet Connection Required

This software requires an Internet Connection for license activation and verification.

Successful license verification isn't required every time you use the software, but it is needed during installation and needs to succeed once every couple of weeks to keep the license fresh.

The license can be "revoked" to remove it from one machine so it can be moved on to another. You should also do this if you're updating your system in case the machine appears to have changed identity.