Some BMW car has a middle speaker (dash speaker) for the sound of the original navigation system. In this case, if you install the Android screen in normal way, it has some noise in the speaker in Dual-Zone mode (using OEM music + Android GPS at the same time).
Note: It work well when using Android music + Android GPS.
How to check if the car with the middle speaker?
If the car has a cover on the dashboard (photo below), it might be a middle speaker under the cover. But you need to check if it really has a speaker inside or not, maybe it is just a cover only.
You can remove the cover and check it, or just put the phone on top of the cover and record the music or navigation voice, that is easy to know if there is a real speaker inside or not.
To resolve the noise problems, there are 3 solutions.
1, Solution1: Offer the power cable with middle speaker connector.
For some car types, we can offer the power cable with 2 connectors.
For now, BMW 5 series / 6 series / 7 series, X5, etc, since most of them with middle speaker, thus we normally offer the power cable with 2 middle speaker connectors shown as below.
2, Solution 2 : Add a small navigation speaker & modify the power cable.
If your middle speaker not only with the sound of OEM navigation, but also with the music, and want it continue to work (instead of becoming a specific android navigation speaker), we can modify the power cable and add an external small speaker for Android navigation. See below. Let us know if you need this solution.
(modified power cable with a small speaker for android navigation)
3, Solution 3: Modify the power cable on your own.
If you have bought the android screen, but the car with a middle speaker, In this case, the only way is to modify the cables on your own:
A, Modify the cable according to the instructions below and connect to your middle speaker (that way, the middle speaker will be a specific speaker for android navigation).
B) Modify the cable according to the instructions and add an external small speaker (as the solution 2 as mentioned above).
Please check the steps as below:
1), Find out this 4 cables (the connector which connects to the back of the android screen)
2), Cut these 4 cables
Connect 4 cables as below:
Blue & White
blue(with black line) & white (with black line)
4), Another side (the side near to the white connector), will connect it to the middle speaker. details showed as below photo:
If your car with a middle speaker, but you don't modify the cable, it is ok if when use Android music + Android GPS, just when you use OEM music + Android GPS, it has noise in speaker.
Remark: If your car doesn't have a middle speaker, then no need to modify the cables like this, all will be plug and play, the GPS sound from the front left speaker, and the radio come from other speakers without interference.