O3A Spotlight Split

O3A Spotlight Split

Host Support

Host TypeSupport


Output32Two split O3A mixes



This plugin is a variant of the O3A Spotlight plugin. Whereas that plugin produces 16 channels of output containing a single O3A scene, this plugin produces 32 channels of output, containing two O3A scenes.

The first 16 channels of the output contain the spotlit scene as before, but the others contain the rest of the original scene. These two sets of channels can be mixed back together to reconstruct the original input mix with the O3A Join plugin.

This can be useful when you want to apply processing just to the spotlit region, leaving the rest of the original scene intact. In Reaper, placing a normal 16 channel O3A manipulator on a 32 channel track applies the manipulator to the lit region (the first 16 channels) only and the unlit region passes through unaffected. These can then be joined back together.

The plugin is available in the O3A Manipulators plugin library.

View Support

When used with O3A View Sync from the O3A View library, this plugin can be connected to the separate View or ViewVR applications.

When this option is available, a 'View' button appears at the top right of the plugin's user interface.

View button

When this is pressed, the plugin is connected to the View or ViewVR application and is displayed there.

View SupportViewVR Support

The current direction is shown using a cross.

Hold the left mouse button to set the azimuth and elevation.

The current direction is shown using a beam and cross.

Hold a VR controller trigger to set the azimuth and elevation.


Controls: Azimuth and Elevation

Azimuth and Elevation control the direction to be kept in the first audio scene (the rest is passed to the second).

Azimuth is the horizontal angle, between -180 to +180 degrees, measured anticlockwise (left) from the front. Elevation is a vertical angle between -90 and +90 degrees, measured with positive upwards and 0 on the horizontal.

For instance, the direction for azimuth +90 and elevation +45 can be found by turning 90 degrees to the left and then looking up by 45 degrees.

Control: Width

Width is an angle, between 0 and 180 degrees, indicating how wide the beam of the spotlight should be. An angle of 0 indicates a narrow beam and an angle of 180 encompasses the whole scene.

Angles are measured from the spotlight direction to the sound direction. When the angle is less than the width setting, the sound is in the lit region and should be kept. Other sounds are in the unlit region and should be attenuated. In practice, the transition from the lit to unlit region is a gradual slope rather than a hard transition.

Control: Flip

Enabling this switch flips the meaning of the lit and unlit regions.