As far as I can tell, there are currently are 7 audio streams in Android:
STREAM_ALARM (for alarms)
STREAM_DTMF (for DTMF Tones)
STREAM_MUSIC (for music playback)
STREAM_NOTIFICATION (for notifications)
STREAM_RING (for the phone ring)
STREAM_SYSTEM (for system sounds)
STREAM_VOICE_CALL (for phone calls)
I also know that it is possible to explicitly tell the TTS engine which stream to use:
params.put(TextToSpeech.Engine.KEY_PARAM_STREAM, String.valueOf(AudioManager.STREAM_ALARM));
mTts.speak(text, TextToSpeech.QUEUE_ADD, params);
What I couldn't find, however, is what stream is used by default when I don't specify an audio stream.
What is the default audio stream from Android's TextToSpeech engine?
Is there a way to query which stream is currently being used by Android's TextToSpeech engine?
UPDATE: TextToSpeech.Engine has a constant defined as DEFAULT_STREAM but it is unclear which of the 7 streams it is referring to. It has the same hex value (0x3) as STREAM_MUSIC, though. Is this it?