How do you control the volume of ApplicationMusicPlayer?

I need to duck the audio coming from ApplicationMusicPlayer while playing a local file using AVAudioPlayer.

I've tried using the duckOthers option as follows, but it doesn't work:

	let appAudioSession = AVAudioSession.sharedInstance()

	do
	{
		try appAudioSession.setCategory(.playAndRecord, mode: .default, options: .duckOthers)

Maybe this is because there's one session for the entire app, and ApplicationMusicPlayer is using it?

This is a fairly critical problem for my application, since Music content is always much louder than locally recorded content. Any insight appreciated.