Fibre Optic stopping CarPlay audio

[z4lincs]

Hey!

I’ve installed an aftermarket CarPlay screen and Vibe powerbox amp and all works fine, except after about 5-10 seconds the audio fades out and stops, whilst the song keeps playing in the background.

If I physically plug my phone into the aux in, this doesn’t happen. Weirdly, it works fine wirelessly if the fibre optic cable is not plugged in (although you get weird speaker static) but as soon as the fibre optic is plugged back in, give it 5 secs, and the sounds fades out.

Any ideas as I’m totally at a loss!

[AnubisZed]

As both the Powerbox amp and (I assume) the carplay unit have Quadlock Y looms, then I'd disconnect one and see how it goes, then swap them around and see from there.
Theoretically they should both work fine together. There could be a fault with either the amp or mmi box.
Did you swap the fibre optic to whichever Quadlock goes into the rear of the headunit?

[z4lincs]

As both the Powerbox amp and (I assume) the carplay unit have Quadlock Y looms, then I'd disconnect one and see how it goes, then swap them around and see from there.
Theoretically they should both work fine together. There could be a fault with either the amp or mmi box.
Did you swap the fibre optic to whichever Quadlock goes into the rear of the headunit?

So yes, with the amp totally disconnected the CarPlay audio works fine wirelessly. Obvs can’t test the other way round as don’t have wireless without the new screen.

I have swapped the fibre optic cable into whichever quadlock is going into the headunit, and tried both ways of either amp being the last connection or the screen.

Is there any chance I need to get another fibre optic cable so it runs through the extra quadlock join because of the amp??? Instead of straight from car to headunit..

[AnubisZed]

So yes, with the amp totally disconnected the CarPlay audio works fine wirelessly. Obvs can’t test the other way round as don’t have wireless without the new screen.

I have swapped the fibre optic cable into whichever quadlock is going into the headunit, and tried both ways of either amp being the last connection or the screen.

Is there any chance I need to get another fibre optic cable so it runs through the extra quadlock join because of the amp??? Instead of straight from car to headunit..

Depending which options your car has (everything was an option!!), you only need the OE fibre optic in the Quadlock that goes into the headunit, as this connects to other modules within the car (MULF (Bluetooth calls), TV Module, External DAB Module, etc). The fibre optic is not required for the Powerbox amp, as it's not an optical connection, it only runs from the speaker wires in the Quadlock speaker outputs section.

The Quadlock Y looms work by a "pass-through" method, as in all wires that come into it pass directly to the other end, with some being piggy-backed (normally power and can-bus), but in the case of the Powerbox loom it interupts the speaker wires coming from the headunit, redirects them to the amp and then outputs the amplified signal back to the outgoing wires.
The Y loom for the CarPlay screen is a straight pass-through loom just with the piggy-backs for power and can-bus.
So with that in mind neither of them should interfere with the other.

How is the audio output from the screen being outputted? Normally it's either an AUX lead to the AUX socket in the centre console, or a direct input into the Quadlock, again this is dictated by what equipment options are fitted.

[z4lincs]

So yes, with the amp totally disconnected the CarPlay audio works fine wirelessly. Obvs can’t test the other way round as don’t have wireless without the new screen.

I have swapped the fibre optic cable into whichever quadlock is going into the headunit, and tried both ways of either amp being the last connection or the screen.

Is there any chance I need to get another fibre optic cable so it runs through the extra quadlock join because of the amp??? Instead of straight from car to headunit..

Depending which options your car has (everything was an option!!), you only need the OE fibre optic in the Quadlock that goes into the headunit, as this connects to other modules within the car (MULF (Bluetooth calls), TV Module, External DAB Module, etc). The fibre optic is not required for the Powerbox amp, as it's not an optical connection, it only runs from the speaker wires in the Quadlock speaker outputs section.

The Quadlock Y looms work by a "pass-through" method, as in all wires that come into it pass directly to the other end, with some being piggy-backed (normally power and can-bus), but in the case of the Powerbox loom it interupts the speaker wires coming from the headunit, redirects them to the amp and then outputs the amplified signal back to the outgoing wires.
The Y loom for the CarPlay screen is a straight pass-through loom just with the piggy-backs for power and can-bus.
So with that in mind neither of them should interfere with the other.

How is the audio output from the screen being outputted? Normally it's either an AUX lead to the AUX socket in the centre console, or a direct input into the Quadlock, again this is dictated by what equipment options are fitted.

Thank you for such a detailed reply! The audio output of the screen is straight into the Quadlock.

Having put the car back together last night and driven this morning, I had no audio again and this was without the amp connected, so christ knows what's going on...

Is there any chance a fibre optic loop connection like this (https://amzn.eu/d/6lHFe2v) inserted into the headunit might solve the problem? as I have none/don't need any of the options the FO seems to feed

[AnubisZed]

Thank you for such a detailed reply! The audio output of the screen is straight into the Quadlock.

Having put the car back together last night and driven this morning, I had no audio again and this was without the amp connected, so christ knows what's going on...

Is there any chance a fibre optic loop connection like this (https://amzn.eu/d/6lHFe2v) inserted into the headunit might solve the problem? as I have none/don't need any of the options the FO seems to feed

OK, so if that's the case I take it you don't have bluetooth (calls) or the centre console USB, just the AUX? If that's correct, then you don't have anything on the fibre optic network, so this is not a fibre optic issue.

Right, so if you make sure then that the Quadlock that goes directly into the rear of the headunit is the one from the screen, then that means that the audio output from the screen will go directly into the headunit (AUX on-board input), then the speaker output from the headunit will go out and pass-through the screen Y loom and then into the amp quadlock where it will be intercepted, then output from the amp to the speakers (again, hopefully that makes sense).

If that doesn't improve things, do you have this connection on the screen Y loom?...

wire.jpg (97.64 KiB) Viewed 207 times

or

wire2.jpg (42.6 KiB) Viewed 207 times

This would then run through the centre console to the AUX socket under the armrest, so you could try this method.

[z4lincs]

Thank you for such a detailed reply! The audio output of the screen is straight into the Quadlock.

Having put the car back together last night and driven this morning, I had no audio again and this was without the amp connected, so christ knows what's going on...

Is there any chance a fibre optic loop connection like this (https://amzn.eu/d/6lHFe2v) inserted into the headunit might solve the problem? as I have none/don't need any of the options the FO seems to feed

OK, so if that's the case I take it you don't have bluetooth (calls) or the centre console USB, just the AUX? If that's correct, then you don't have anything on the fibre optic network, so this is not a fibre optic issue.

Right, so if you make sure then that the Quadlock that goes directly into the rear of the headunit is the one from the screen, then that means that the audio output from the screen will go directly into the headunit (AUX on-board input), then the speaker output from the headunit will go out and pass-through the screen Y loom and then into the amp quadlock where it will be intercepted, then output from the amp to the speakers (again, hopefully that makes sense).

If that doesn't improve things, do you have this connection on the screen Y loom?...
wire.jpg
or
wire2.jpg

This would then run through the centre console to the AUX socket under the armrest, so you could try this method.

I do have the usb port and bluetooth calls, although neither are used/phone connected. I'll get the dash apart again and check the cabling is set up as per your advice, although I'm pretty sure I've tried every combination. Re the loom and aux-in, it has the one in your first example and is connected.

Thanks again! I've got family obligations tonight, but can hopefully have a look again tomorrow and shall update

[AnubisZed]

Arr, right so you've got the AUX lead plugged in the socket in the armrest and you have USB and Bluetooth calls, in that case you need the fibre optic connected.

[z4lincs]

Arr, right so you've got the AUX lead plugged in the socket in the armrest and you have USB and Bluetooth calls, in that case you need the fibre optic connected.

So, finally got somewhere and using this little looping fibre cable, problems all solved! Dab still works as I guess internal rather than external, and I've just lost BT phone but I use that through the CarPlay anyway now

IMG_4666.JPG (192.28 KiB) Viewed 164 times

Just successfully followed your speaker upgrade vid too, so it's a good day today!

[AnubisZed]

So, at a guess then I'd say you've possibly damaged one of the fibres, as it would be a huge coincidence for the MULF to go faulty at the same time you added the new parts in.
Glad it's working for you though

[B21]

Generally you can’t have car play and the original blue tooth..unless you have two phones..afaik

[AnubisZed]

Arr, right so you've got the AUX lead plugged in the socket in the armrest and you have USB and Bluetooth calls, in that case you need the fibre optic connected.

So, finally got somewhere and using this little looping fibre cable, problems all solved! Dab still works as I guess internal rather than external, and I've just lost BT phone but I use that through the CarPlay anyway now

IMG_4666.JPG

Just successfully followed your speaker upgrade vid too, so it's a good day today!

I've just thought of something,
If you've bypassed the fibre optic, by adding the loop, then the AUX normally goes to the MULF, but if that's the case then you wouldn't hear anything from your screen if it's plugged into the AUX socket! So if you can still hear it and, as you've shown in the photo, you have bypassed it, then the AUX must actually go directly to the Quadlock instead of the MULF.... yest another BMW anomaly

[z4lincs]

Arr, right so you've got the AUX lead plugged in the socket in the armrest and you have USB and Bluetooth calls, in that case you need the fibre optic connected.

So, finally got somewhere and using this little looping fibre cable, problems all solved! Dab still works as I guess internal rather than external, and I've just lost BT phone but I use that through the CarPlay anyway now

IMG_4666.JPG

Just successfully followed your speaker upgrade vid too, so it's a good day today!

I've just thought of something,
If you've bypassed the fibre optic, by adding the loop, then the AUX normally goes to the MULF, but if that's the case then you wouldn't hear anything from your screen if it's plugged into the AUX socket! So if you can still hear it and, as you've shown in the photo, you have bypassed it, then the AUX must actually go directly to the Quadlock instead of the MULF.... yest another BMW anomaly

Who knows eh, but it works, so I’m happy! Thanks again for all your help

One final question as I can’t seem to find a definitive answer for the e89, if I decide to, can you use BimmerCode to code for hifi, or is the only the other ways discussed on other topics.

[AnubisZed]

...
One final question as I can’t seem to find a definitive answer for the e89, if I decide to, can you use BimmerCode to code for hifi, or is the only the other ways discussed on other topics.

Alas I don't use Bimmercode so I don't know.
What I do know though is that when I tried coding in the HiFi option (676) without the external amplifier, it sounded aweful, well it did to me. Personally it sounds far better without it, IMHO But no harm in trying