O3A Upmixer - 5.1

O3A Upmixer - 5.1

Host Support

Host TypeSupport
AAXYes
VST2Yes

Audio

ChannelsContent
Input65.1 Surround
Output16O3A

Controls

Description

This plugin takes a surround mix prepared for a 5.1 system and converts it to third order ambisonics (O3A).

Channels

The channel ordering used is:

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

The plugin is available in the O3A Upmixers plugin library.

Controls

Control: Corners

The corner layout lets you tell the processor how the 5.1 mix was prepared, as this can help the accuracy of the spatial imaging. ITU is the most common option.

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: Mode

Three modes are supported, "Inferred", "Studio" and "Virtual". Generally, "Inferred" or "Studio" are recommended.

ModeDescription
InferredThis mode is optimised for use with material that has been mixed using conventional panning techniques, such as equal-power panning or VBAP. The approach produces smooth transitions when sounds pass between speaker locations.
StudioThis mode is optimised for use with material that has been mixed using 'pairwise' panning, for instance in Pro Tool Ultimate's surround panner. The approach produces smooth transitions when sounds pass between speaker locations. In this mode, the corner layout is always assumed to be Square.
VirtualThis mode simply places each of the main (non-LFE) audio channels in their appropriate speaker direction. This can be worth trying when the mix has not been put together by conventional panning and the channels have a complex phase relationship.

Control: LFE Gain

Audio from the LFE channel can be mixed into the output by setting this dial. It is added to the stream as an omnidirectional signal.