S9 Bluetooth car head unit disconnecting problem

[James Symington]

Hello,

I used to have an S7, which I used in my car with bluetooth. I recently upgraded to an S9 and its having a few disconnection problems.

When listening to music the head unit will randomly disconnect from the phone, even though both my phone and the units bluetooth is still on. It'll reconnect a few moments after clicking reconnect on the head unit.

My phone doesn't do this to other bluetooth devices so I suspect the head unit is the problem (Sony Xav651bt). But the head unit will work perfectly with other phones - although I'm yet to try another S9 on my car.

I've tried to check the Bluetooth version(?) of both the head unit and my S9 but I believe they are compatible.

I've reset the profiles on the head unit and my phone, to ensure its not being interfered by another paired device. I've also cleared the bluetooth cache and data through my S9's settings. Still no success.

I've had no help asking Sony forums so I thought I'd take a chance to see if anybody here has had a similar problem.

 

[lucianus_luciferus]

There are a few Bluetooth settings you can change in the developer options. I would try them one by one and see if it makes any difference.

 

[shelwe]

I have the exact same problem as OP. My devices are Opel w/ IntelliLink head unit, S9+, Ticwatch E (wear 2.0).
After switching from LG G5 to the S9+ I started noticing that the head unit and the S9+ lost Bluetooth connectivity for 10 seconds, reconnected automatically, disconnected again after a random time period and repeated until at some point they completely refused to re-connect (regardless of any music being played over Bluetooth or not).
After, ALOT, of debugging, resetting the head unit, going to the dealer for an upgrade, changing every BT option on the S9+ - the issues persisted.

TLDR; I found that if I put the Ticwatch E into airplane mode when entering the car I have no more issues with the phone and head unit. This leads me to think that it might be the S9+ not correctly handling 2 BT devices concurrent connections.

While I have not yet checked any of lucianus_luciferus' recommendations, I'd appreciate anyone that had similar issues confirm or deny my suspicions.

Thanks,

 

[CamSutton75]

Hello,

I used to have an S7, which I used in my car with bluetooth. I recently upgraded to an S9 and its having a few disconnection problems.

When listening to music the head unit will randomly disconnect from the phone, even though both my phone and the units bluetooth is still on. It'll reconnect a few moments after clicking reconnect on the head unit.

My phone doesn't do this to other bluetooth devices so I suspect the head unit is the problem (Sony Xav651bt). But the head unit will work perfectly with other phones - although I'm yet to try another S9 on my car.

I have the exact same problem with the exact same car stereo (Sony Xav651bt) - but ironically it's the S7 I've just upgraded to, after having no issues with my previous S5 mini. Driving me nuts. It makes me want to go back to the S5 mini despite the S7 being far superior in every other way. I thought maybe is was the Songpal app so I tried it without that, still the same problem. Argh. Have you had any luck?

 

[CamSutton75]

The main thing I'm wondering is: Are you using the Sony Songpal app? There's some settings in there about giving LDAC 900kb settings prority, potentially at the expense of a connection. I changed those settings and thought I'd fixed it. I got through most of the afternoon without a drop-off, but then right when I got home, it dropped off. So frustrating! I have also tried clearing all the cache and data from the Bluetooth app on the phone, and reconnected the head unit. Still having the issue. We've both upgraded phones, and while we've upgraded to different phones, I wonder if transferring settings has something to do with it.

 

[CamSutton75]

What I think at this point of my journey to figure this out is that it's not your phone, it's Oreo.

 

[CamSutton75]

OK, I THINK I might have an answer. Android 8.0 Oreo supports different Bluetooth codecs. These include a new 'high quality' codec called LDAC. The Sony headunit doesn't support LDAC. The Songpal app has a setting that automatically defaults to LDAC. So first I switched that setting off, and everything about prioritizing LDAC. That seemed to help but I was still getting drop offs occasionally so this may not be helpful.

Then I discovered that you can access a developers menu in Oreo. You do this by going to settings -> about phone -> scrolling to the build number and tapping on it 7 times. Sounds like something out of Harry Potter, but it then tells you 'you are now a developer' and gives you a whole bunch of options you probably don't want to touch.

So if you go to the developers menu and scroll down the list of settings, you'll find a Bluetooth Codec setting. Check this video if you're having trouble: https://www.youtube.com/watch?v=zVK4UIHOEGE

I checked the manual for the Sony head unit, and it's default codec is SBC. Mine was defaulting to AAC. Now if you change that setting to SBC, or any other setting, while you're away from your headunit, it does nothing. It will change, but if you go out of the menu and back in you'll find it's switched back to AAC.

BUT.... if you go into the car, pair the phone to the head unit, play some audio, THEN go into that menu, you can switch between compatible settings. It won't let you switch to ones it doesn't work with, with this head unit you can only switch between AAC and SBC. As you switch between them while playing audio you can hear the unit changing between the Codecs. If you switch to SBC while the unit is playing, the phone seems to keep that setting.

So it appears that the Sony head unit unit will run on AAC, but it prefers SBC, which is apparently the previous standard setting everything pretty much ran on. Since I did this I haven't had a drop off. BUT it's early days. I did it last night and have only made a few short trips. So we'll have to wait and see. But before it was dropping off constantly, so here's hoping this is a fix!

 

[CamSutton75]

SUPPOSEDLY there is also this setting, which would seem to be an easier way to do this:

Navigate to Settings > Connected devices > Bluetooth.
Tap on the gear icon next to the sink you want to disable codecs for.
Uncheck the HD Audio checkbox

But I can't find an HD Audio checkbox anywhere. I don't know if AAC qualifies as HD audio or not anyway.

 

[CamSutton75]

OK, talking to myself here it seems, but updating this anyway. This definitely did NOT fix the problem for me. I am still getting regular drop offs. What's more frustrating is that I had quite a long drive with my son and we tested his considerably cheaper Xiaomi on our car stereo, not a single disconnect. Makes me want to sell my S7 and get a Xiaomi (or go back to the S5 mini I gave my daughter), despite the S7's awesome camera. The Xiaomi is running Android 8.1 though, so we can only hope and pray that Samsung gives us an 8.1 update soon and that fixes the issue. Pretty **** poor considering how advanced these phones supposedly are. I've tried every suggestion on the net and gotten nowhere.

 

[CamSutton75]

SOLVED (kinda)

Right, in case anyone else ever needs this thread in future, it is DEFINITELY related to SBC/AAC. I realised that I was getting disconnects again because my phone (Oreo) was defaulting to AAC. So if you change it to SBC via the above method when the unit is connected you shouldn't get drop offs. I drove about 2.5 hours over the weekend without a single disconnect. The problem is I have to change the codec every time I connect my phone to the stereo. So every time I get into my car and turn it on, the phone and stereo automatically connect, but the phone again defaults to AAC. So I have to change it. And then it's fine. So this is not a fix, but it IS a work around. It means short drives I usually just listen to the radio or put up with the odd disconnect, longer drives I'll switch the codec to SBC before I go and not have any problems. Hopefully the next software update will fix this problem, if the S7 ever gets it in my case, but in the meantime, this is what you need to do.