O3A Decoder - 7.1.2 (Dolby Atmos)

Host Support

Host Type	Support
AAX	Yes
VST2	Yes

Audio

	Channels	Content
Input	16	O3A
Output	10	7.1.2 (Dolby Atmos)

Controls

Method
LFE Crossover
LFE Gain

Description

This plugin takes a third order ambisonics (O3A) mix and decodes it as 7.1.2.

7.1.2 is a standard mix format for beds in Dolby Atmos. It adds two ceiling channels to standard 7.1.

Channels

The channel ordering used is:

Channel	AAX	VST
1	Front Left	Front Left
2	Front Centre	Front Right
3	Front Right	Front Centre
4	Left Surround Side	LFE
5	Right Surround Side	Left Surround Rear
6	Left Surround Rear	Right Surround Rear
7	Right Surround Rear	Left Surround Side
8	LFE	Right Surround Side
9	Left Top Surround	Left Top Surround
10	Right Top Surround	Right Top Surround

Please note that the channel ordering used by Dolby's Atmos RMU may differ. Also, the AAX order above is used when plugins interact with ProTools through the AAX software interface; other parts of ProTools may use a different default order, for instance when exporting to file.

The plugin is available in the O3A Decoding plugin library.

Controls

Control: Method

Three methods are supported, "Basic", "Reconstruction" and "Tinted Reconstruction". Generally, "Basic" is recommended except where the speaker rig to be used for playback is known and has been set up accurately.

Method	Description
Basic	This method produces a resilient decoding which should play well on a range of speaker systems including large venues.
Reconstruction	This method controls the soundfield at the centre of the listening space to produce a clearer spatial image. It relies on the speaker layout being set up accurately.
Tinted Reconstruction	This variant of the Reconstruction method performs HRTF-based tinting on the audio stream to strengthen the spatial image. Again, it relies on the speaker layout being set up accurately.

Control: LFE Crossover

This determines if any audio is sent to the LFE channel. It may be set to "Off" and this is recommended. If enabled, audio is extracted from the main mix into the LFE channel using the indicated crossover frequency (between 1 and 200Hz).

Control: LFE Gain

If the LFE gain is active, this gain is applied to it. Some export formats may need this set to -10dB to take into account a +10dB gain applied during playback.

O3A Decoding