dualRoute
A mode that provides simultaneous use of the built-in microphone/speaker and a secondary audio device that supports input and output.
Declaration
static let dualRoute: AVAudioSession.ModeDiscussion
This mode can only be used with the multiRoute category. It additionally requires you to set the allowBluetoothHFP option.
Enabling this mode results in the following behavior:
The primary audio route is always the built-in microphone/speaker.
The supported secondary route types are headsetMic, headphones, bluetoothLE, and bluetoothHFP.
Only audio routes that support input and output are available for use.
The hardware volume controls adjusts the volume for both primary and secondary routes.
The system may engage appropriate signal processing for output routes.