I'm using the TTS Library in my app. When output (speaking) is generated, it's at the same volume as any existing audio. Is there any way to mute the existing audio during TTS output? I imagine it might be with the Phone Library somehow?
You can use Phone.SetVolume to change the volume of other channels. If I remember correctly, TTS uses the VOLUME_MUSIC channel.
Note that you should expect exceptions when calling Phone.SetVolume. You must catch them with Try / Catch.