O1A Decoder - 5.1

O1A Decoder - 5.1

Host Support

Host TypeSupport


Output65.1 Surround



This plugin takes a first order ambisonics (O1A) mix and decodes it as a 5.1 surround mix.


The channel ordering used is:

1Front LeftFront Left
2Front CentreFront Right
3Front RightFront Centre
4Left SurroundLFE
5Right SurroundSide Left
6LFESide Right

The plugin is available in the O1A Decoding plugin library.


Control: Corners

The corner layout lets you tell the processor where the corner speakers for 5.1 playback are assumed to be:

Corner LayoutDescription
ITUIn principle, the speakers of a 5.1 system should be set out using ITU angles. From front centre, this recommends front left and right speakers be at +30 or -30 degrees and side speakers be at +110 or -110 degrees. ITU layouts are common in studios and are a common way to mix 5.1.
SquareIn practice, many 5.1 speaker systems are set up with the corner speakers set out in what is roughly a square and some mixes are put together on this basis. If you know that's the case, switch the corner layout to Square.

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.

BasicThis method produces a resilient decoding which should play well on a range of speaker systems including large venues.
ReconstructionThis 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 ReconstructionThis 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.