Navigator voice prompts via Bluetooth

Question

Bluetooth

There is an android phone and a regular speakerphone in the car via Bluetooth. Receives / makes voice calls, plays music via A2DP, everything is ok with this.
But there is one drawback, the playback of sounds from the phone is possible only if the appropriate source is selected in the audio system. And I would like to constantly play music from USB in the car, but if necessary, the phone could say the message of the navigator, he could do it.
Is such a possibility provided in the bluetooth protocol in principle and maybe there is the right software?

An incoming call is received on the audio system regardless of the selected source, maybe there are mechanisms for voicing messages without ringing?

Answer 1

Probably, it is necessary to pick software.
If all the sound on the BT headset has been normally distilled since the days of WM 6, then with a modern android and a bunch of its firmware and software, I think there will be no problems.

Answer 2

Found the application play.google.com/store/apps/details?id=com.turboled.audiobt really works, transmits sound through the HSP profile, and the car system just thinks that there is a call and plays it interrupting the music.
True, after the end of the playback of the navigation prompt, the audio system continues to think for another 4 seconds that there is a conversation going on, which is not very convenient.
And the program itself works exclusively with Google navigation.