HERE Maps (voice navigation + radio) - How To?

HERE Maps
Xperia Z1 Lolipop 5.1.1
Beta Version 2.6.5.9

What are the settings needed to hear voice navigation from the car speakers while listening to the car radio for HERE Maps and Xperia Z1 Lolipop? I tried setting to Bluetooth Mono but it didn't work and the voice navigation came out through the phone speakers instead. "Speaker" was NOT selected - only "Let app decide" and "bluetooth mono". TTS setting was SoundAbout and Google TTS.

In HERE Maps under Settings - Voice Options - Manage Voices - there are other voices which can be downloaded but I do not see com.woodslink.android.wiredheadsetphone.

I tried HERE maps.  They do not use the default Android Text-To-Speech engine.   It looks like they only use an internal TTS engine and only let you choose their voices to download.

If they do not call into an outside TTS engine, then SoundAbout has no way of knowing when they are about to play navigation directions.  Without a way to detect a request for navigation to be converted to audio, SoundAbout doesn't have a way to switch the audio to Bluetooth and then allow the text to be converted to audio AFTER the audio has been switched.

I can confirm that AudioBT works with HERE Maps.

There are two ways of using AudioBT.

-One is a background service that monitors the audio focus and turn on the Bluetooth SCO proile when another app is temporarily requesting the audio focus. Unfortunately the first second of the audio might be cut when using this service (to be fixed with upcoming Xposed hook). Some applications do not request the audio focus properly so this might not always work.

-The other approach is an integrated TTS engine. Any app using tne Android TTS service can use the AudioBT TTS service for sending text to speech. AudioBT will automatically turn on the Bluetooth SCO profile before playing the text. Any TTS service or language can be selected in the AudioBT TTS parameters.

I do not know which way it's using but it's possible.

AudioBT says there are two ways.   The one that is working is the first one (where it uses audio focus).  It can't use Text To Speech because HERE doesn't support 3rd party TTS engines (which would work better).

When you use audio focus, the app will detect the audio being played (navigation) and then switch the audio to Bluetooth.  The switch to Bluetooth takes a couple seconds, so you will lose some of the directions.  

When the navigation app uses TTS,  the SoundAbout TTS engine (same for Audio BT) will wait until AFTER the audio is switched to transform the text into audio.

To accomplish the same thing as Audio BT (using audio focus), you would change SoundAbout's "Media audio" setting to "Bluetooth (mono) (dynamic)".  Like I said, this will most likely miss 1-2 seconds of the directions.  

AudioBT says the same thing: Unfortunately the first second of the audio might be cut when using this service

The phone is paired with the car through bluetooth and the phonebook is downloaded from the phone to the car. Without using SoundAbout, voice and music can come out through the car speakers through the bluetooth channel.

But setting SoundAbout's Media audio setting to Bluetooth (mono) (dynamic) OR Bluetooth (mono) makes the sound come out from the phone speaker.

Setting  Connectable devices - bluetooth setting - Media audio behavior - Bluetooth (mono OR dynamic) also makes the sound come out from the phone speaker.

BTAudio has an Xposed hook to avoid the loss of the first 2 seconds of voice navigation.

I will look at Xposed again.  The issue is, to use Xposed, the phone needs to be rooted.