O3A Decoder - N3D

Host Support

Host Type	Support
AAX	Yes, output mapped to standard SN3D ambisonics
VST2	Yes

Audio

	Channels	Content
Input	16	O3A
Output	16	N3D/ACN Ambisonic Audio (mapped to standard SN3D ambisonics for AAX)

Description

This plugin takes a third order ambisonics (O3A) mix and converts it to a third order "N3D" ambisonic mix. N3D is a close relative to SN3D, which is used natively by these plugins. The "ACN" channel ordering convention is used in both cases.

We have labelled this plugin as a decoder hopefully to make it clear that its output is an external format and no longer compatible with the convention that the rest of these plugins use.

In Pro Tools, as the N3D format is not supported directly, this plugin outputs audio using the ordinary ambisonic stem format. Normally this should be encoded as O3A (i.e. SN3D/ACN), so we are "misusing" the format here.

N3D is used in MPEG-H 3D Audio.

Warning

Please be aware that N3D and SN3D are similar to each other, but not the same. Be very careful to convert where necessary as it may not be immediately obvious if mistakes are made. Do not guess! If you get this wrong it is likely to result in level, blurring or sharpening errors which may not be immediately obvious on simple decoders.

Other Conventions

Note that other plugins are available to convert to and from ambisonics using the FuMa convention. See O3A Decoder - FuMa and O3A Injector - FuMa.

Orders

This plugin produces third order N3D output. If you only want first or second order output, just take the first four or nine output channels and ignore the rest.

Alternatively, the O3A Decoder - O1A or O2A plugins from the O3A Core can be "misused" to reduce the order of the N3D material as this is a rare case where a plugin will work correctly for both SN3D and N3D.

The plugin is available in the O3A Decoding plugin library.

O3A Decoding