O3A Harpex Upsampler

This plugin takes classic first order ambisonic material and converts it to third order ambisonics (O3A) using the Harpex algorithm.

This allows recordings made with first order, four channel ambisonic microphones to be converted to high resolution, third order, sixteen channel mixes which can then be sent to other O3A plugins such as the O3A Manipulators or O3A Decoding plugins.

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

Meters are provided, showing the energy content in each ambisonic order, before and after upsampling.

This plugin use the SN3D ambisonic convention for its output, at third order.

We use some free software in this product. Before purchase, please check the license agreement. Prices include VAT where applicable. EU VAT is normally charged at your local rate using the MOSS VAT system, but please get in touch before purchase if you need a business-to-business transaction. By beginning the payment process you agree to be bound by our terms and conditions.

O3A Harpex Upsampler

Plugin List

O3A Harpex Upsampler

I/O: 4 in, 16 out

This plugin upsamples first order ambisonic material to third order (O3A).

O3A Harpex Upsampler

Tech Requirements

O3A Plugin Technical Requirements

Please check that everything is okay here before purchasing software.

Operating System

Supported versions of Microsoft Windows are Windows 7, Windows 8 and Windows 10. Supported versions of Apple macOS X are 10.7 or later, Intel only. The VST plugins are available in 32bit or 64bit forms on both platforms (packaged as a Universal Binary on macOS). The AAX plugins are 64bit only.

VST Host

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

These plugins do not work with all VST 2 hosts. One reason for this is that the O3A plugins need large numbers of channels on their input or output busses. Check the individual plugins for the channel counts they need, but all of the O3A plugins need at least 16 channels on each track, and a few need more. 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 or Cubase.

AAX Host

The AAX plugins require Pro Tools Ultimate, or Pro Tools HD v12.8.2 or later.

Due to channel and stem restrictions, not all plugins are supported in AAX. Please see the documentation for details.

PC Hardware

Please check your PC meets the following requirements:

  • Intel Pentium D CPU or better.
  • 200MB of free disk space.
  • Internal network card.

Internet Connection Required

These plugins require an Internet Connection for license activation and verification. We don't really like this, but we can't think of a better way to discourage piracy! Please don't hack our code, it's taken a lot of effort to get it this far...

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.


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