Galaxy S4 TTS output causes disconnect from car radio

I have a Samsung Galaxy S4 which connects both phone and media to my car radio (2013 Camry).  I would like to get Google Nav to send its output (TTS) through the phone connection so it will interrupt whatever is playing on the radio.

So:  without Soundabout, everything connects and functions as you would expect (that is, I can only hear the Nav instructions if I have the car radio set to bluetooth audio).  An incoming phone call interrupts just as expected even if I had a CD or FM playing on the radio.

With Soundabout everything connects as it should and phone calls work as expected but as soon as Nav issues any directions Bluetooth media and phone both disconnect from the radio.

Is there a setting which is messed up or is this a bug for future fix? I would love to have this working correctly - thanks for any help.

Getting Google Nav TTS output, or any audio to go over Bluetooth phone (mono) when you are not on a phone call is tricky.  You have to basically trick the phone into thinking it is in a call to make it send audio to Bluetooth mono.

I don't know what other SoundAbout settings you have set, so you might want to put them back to default.  You can go into Manage apps, find SoundAbout and clear out the cache and clear data, if you don't remember.

1) Go back into SoundAbout.
2) Click on "Text-To-Speech behavior....".
3) Change "Audio Output" to Bluetooth (mono).
4) You may have to set "Max Utterances per request" to one or two.  This is because Google Nav will request ALL the directions at the beginning of the trip and save them.  If you want the Nav to go on and off, over Bluetooth then you can't let that happen, so this setting will only allow so many utterances at one time.
5) I set the "Delay utterance (secs)" to 1.5 or 2 because it takes a second or two for Bluetooth (mono) to reconnect.
6) One time, you will have to click on "Android TTS settings" and choose "SoundAbout TTS".  You can click on the settings icon to the right of the SoundAbout TTS title and then go into the "Settings for SoundAbout TTS" and choose the REAL engine that you want to use for TTS.

Now, there is no guarantee that this will work as Android can change Bluetooth drivers like they did for Android 4.2.2. My phone had BlueZ and now is using BroadCom. BroadCom doesn't seem to switch back and forth with my car as smooth. It all depends on the phone and car, so it is out of SoundAbout's control at that point.