The listener's vector orientation in the environment.
- iOS 8.0+
- macOS 10.10+
- Mac Catalyst 13.0+
- tvOS 9.0+
The default orientation is with the listener looking directly along the negative z-axis (forward).
A forward vector orientation is expressed as
(0, 0, -1). An up vector is expressed as
(0, 1, 0).
Changing this property result sin a corresponding change in the