AKRESULT __cdecl AK::SoundEngine::SetSecondaryOutputVolume	(	AkUInt32	in_iOutputID,
		AkAudioOutputType	in_iDeviceType,
		AkReal32	in_fVolume
	)

Set the volume of a secondary output device.

Parameters:

	in_iOutputID	Player number (almost all platforms) or device-unique identifier (UserID on PS4).
	in_iDeviceType	Device Type, must be one of the currently supported devices types. See AkAudioOutputType
	in_fVolume	Volume (0.0 = Muted, 1.0 = Volume max)

Wwise SDK 2015.1.9