XAudio2 instance to use for the Wwise sound engine. If NULL (default) Wwise will initialize its own instance. Used only if the sink type is XAudio2 in AkInitSettings.eSinkType.
Shared interface to XAudio2. Pass NULL (default) to let Wwise instantiate its own instance of XAudio2 (recommended). If you want to share the same instance of XAudio2 between Wwise and another module of your game, Wwise ADDREFs it and creates its own XAudio2 mastering voice on this interface.