O7A Harpex Upsampler

The O7A Harpex Upsampler plugin converts first order ambisonic material (O1A) to seventh order (O7A) using the Harpex algorithm.

This allows recordings made with first order, four channel ambisonic microphones to be converted to high resolution, seventh order, 64 channel mixes which can then be sent to other O7A plugins such as the O7A Manipulators or O7A Decoding plugins.

The algorithm used is an "active" one which estimates the sound directions in the first order material and uses that to synthesise seventh order material.

CPU Load Warning

The O7A plugins are similar to the O3A plugins, except for the ambisonic "order" in use. The O3A plugins use third order and 16 audio channels to capture a scene, which already gives high spatial precision. The O7A plugins use seventh order and 64 audio channels, which gives much higher spatial precision but is generally only recommended for research applications, or in studios with high-end modern hardware.

This is a VST2 or AAX plugin for macOS (10.14 to 13.5) or Windows (10 or 11, 64bit Intel). It can be hosted in some Digital Audio Workstations (DAWs) that can handle tracks with sufficiently high channel counts. Because of the very high channel counts needed for these plugins, this typically means Reaper, Pro Tools Ultimate, or Max/MSP. This plugin uses the SN3D higher order ambisonic (HOA) convention, at seventh order, which needs 64 channels.

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O7A Harpex Upsampler

O7A Harpex Upsampler

I/O: 4 in, 64 out

This plugin upsamples first order ambisonics to seventh order.

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

This plugin does not work with all VST 2 hosts. One reason for this is that the plugin needs large numbers of channels on its input or output busses.

AAX Host

The AAX plugin requires Pro Tools Ultimate version 2023.6 or later.

PC Hardware

Please check your PC meets the following requirements:

  • Intel Core i7 CPU or better, or Apple Silicon.
  • 400MB of free disk space.


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.