Using Ambisonics

Ambisonics is a surround sound technique covering the horizontal plane as well as regions above and below the listener. By way of its B-format sound field representation with spherical harmonics, it works independently of speaker setups. Notably, this makes it easy to rotate the sound with the listener. Anywhere a sound designer might need a more spherical sound representation, such as in providing ambient sounds or in developing VR, ambisonics is a viable option.

[Tip] Tip

In addition to the Help material covering ambisonics in this and the following pages, you may find our Ambisonics in Wwise: Overview blog post of great interest. It delves deeper into the theory of ambisonics and how ambisonics can be used in Wwise for VR. Additionally, we offer a few small examples of ambisonics use within the Wwise Sample project, as described here .

Wwise makes it easy to import ambisonic files, submix other configurations to the ambisonics format, and ultimately have an ambisonic output playable on any of an increasing number of platforms which support ambisonics.

To use ambisonic files:

  1. Import ambisonic B-format recorded files, which can be saved either as WAVs or AMBs, as you would any other audio file. Refer to Importing Media Files for more information.

    [Note] Note

    To import ambisonic files (AMB, AmbiX, and WAV files) and validate that they have been properly interpreted as ambisonics by Wwise, open the Source Editor and view or edit the value of the Channel config override menu. To open the Source Editor, on the Contents Editor click the SFX, Music Track, or Voice icon. (Views menu > Contents Editor or Shift+O).

  2. Specify an appropriate Audio Bus to be the Output Bus, as you would for any other sound object. Refer to Specifying the Output Routing for Objects for more information.

    Wwise will mix channels as needed. Refer to Submixing Ambisonics for more information.

To have an ambisonics output:

  1. Set an Audio Bus to have an ambisonics bus configuration of:

    • Ambisonics 1st Order (4 channels)

    • Ambisonics 2nd Order (9 channels)

    • Ambisonics 3rd Order (16 channels)

    • Ambisonics 4th Order (25 channels)

    • Ambisonics 5th Order (36 channels)

    Refer to the Available Ambisonics Bus Configurations table for more information on channel configurations.

    Wwise will mix your source files that are output through the Audio Bus defined above into an ambisonic output.

    [Note] Note

    If your Sound Engine Audio System specified in the Audio Preferences dialog is an Audio Device that supports ambisonics, then you can skip this initial step because the Master Audio Bus will already be set to ambisonics.

  2. Specify a final output device that supports ambisonic channel configurations, such as a 3D binaural system.

    If not an ambisonic-supported output, Wwise automatically decodes the corresponding channel output to the applicable standard output. Refer to Submixing Ambisonics for more information.

Setting the Wwise engine to output an HOA output as its final output

As described above, Wwise produces ambisonic and HOA (higher-order ambisonic) signals when one of the busses' Bus Configuration is set to Ambisonics. These signals are decoded, meaning that they are transformed into a standard multichannel representation, such as stereo or 5.1, whenever a parent bus of an ambisonic bus has its Bus Configuration set to such a standard configuration.

The master Audio Bus inherits the configuration of the end point, which depends on the platform and is usually detected automatically. For now, most platforms will allow only a small selection of output configurations. These are typically stereo, 5.1, and 7.1. So, in general, the Master Audio Bus has a standard channel configuration, which forces decoding of child ambisonic busses to this configuration meaning Wwise will not output HOA directly.

However, it is possible to write a custom Audio Device plug-in that would declare an ambisonics configuration. In that case, a master Audio Bus could have an ambisonics Bus Configuration; therefore, Wwise would preserve, not decode, the HOA signal.

Alternatively, if you only need Wwise to dump the HOA in a file, you can simply insert a Wwise Recorder on an ambisonic bus. The generated file will be in FuMa or AmbiX format, with ambisonic order equal to that of the bus hosting the Recorder.