O3A Decoder - 22.2

Host Support

Host Type	Support
AAX	No
VST2	Yes

Audio

	Channels	Content
Input	16	O3A
Output	24	Hamasaki 22.2

Controls

Method
LFE Crossover
LFE Gain

Description

This plugin takes a third order ambisonics (O3A) mix and decodes it as a 24 channel Hamasaki 22.2 surround mix.

Channels

The channel ordering used is:

Channel	VST
1	Front Left
2	Front Right
3	Front Centre
4	LFE Left
5	Back Left
6	Back Right
7	Front Left/Centre
8	Front Right/Centre
9	Back Centre
10	LFE Right
11	Side Left
12	Side Right
13	Top Front Left
14	Top Front Right
15	Top Front Centre
16	Top Centre
17	Top Back Left
18	Top Back Right
19	Top Side Left
20	Top Side Right
21	Top Back Centre
22	Bottom Front Centre
23	Bottom Front Left
24	Bottom Front Right

Note that 22.2 needs 24 channels in total, which is even more than the 16 that O3A normally needs. Don't forget to check your DAW channel count.

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.

Please note that a further -6dB is applied in addition to this setting to compensate for the presence of two LFEs in the 22.2 configuration.

O3A Decoding