Split microphone connection to share it

Thread Starter

john2k

Joined Nov 14, 2019
146
My car has a overhead mounted microphone for the OEM Bluetooth phone. I have a tablet installed as a infotainment system and I need to connect a TRS microphone to it. The OEM microphone has two wires. Just wondering is it possible to actually run another parallel cable from the OEM microphone and wire it to a TRS jack and have my tablet share the same microphone? Chances of the tablet and the telephone being used together is very slim but what would happen if both devices was using the mic at the same time?

Thanks
 

Dodgydave

Joined Jun 22, 2012
9,951
Try it and see.. the microphone may have a DC bias voltage across it , and may need a
10uF capacitor to decouple it,,worst case scenario it won't work.
 

Thread Starter

john2k

Joined Nov 14, 2019
146
Try it and see.. the microphone may have a DC bias voltage across it , and may need a
10uF capacitor to decouple it,,worst case scenario it won't work.
Ok thank you I will try and tap into the end of the mic wire where it enters the radio and run a cable to the tablet. If i have a 3.5mm TRS jack how do I know which wire of the mic to connect to which pole of the connector? The mic has only two wires but my tablet soundcard seems to need a 3 pole TRS
 

MisterBill2

Joined Jan 23, 2018
8,735
If you connect the microphone to different devices then you are also probably going to have a problem with different common voltages between the two devices. An isolation scheme should work but it will probably be simpler, easier, and more effective to add a separate microphone. Consider that you probably have no data as to the detailsof the OEM microphone system.
 

Thread Starter

john2k

Joined Nov 14, 2019
146
If you connect the microphone to different devices then you are also probably going to have a problem with different common voltages between the two devices. An isolation scheme should work but it will probably be simpler, easier, and more effective to add a separate microphone. Consider that you probably have no data as to the detailsof the OEM microphone system.
Good point thanks.
 

Dodgydave

Joined Jun 22, 2012
9,951
Your Tablet will be in Stereo, so you will have a Left and Right channel and Ground, try one or short them both together to get both channels , as for the radio input the screened wire is the Ground.
 

Thread Starter

john2k

Joined Nov 14, 2019
146
Your Tablet will be in Stereo, so you will have a Left and Right channel and Ground, try one or short them both together to get both channels , as for the radio input the screened wire is the Ground.
Thank you might give it a try. Because ideally I would prefer to utilize the flush nice clean OEM mic then running a external mic. But worse case scenario I guess I will have to run seperate mic
 
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