soloAmbient
The default audio session category.
Declaration
static let soloAmbient: AVAudioSession.CategoryDiscussion
Your audio is silenced by screen locking and by the Silent switch (called the Ring/Silent switch on iPhone).
By default, using this category implies that your app’s audio is nonmixable—activating your session will interrupt any other audio sessions which are also nonmixable. To allow mixing, use the ambient category instead.