2011 OEM Microphone in Overhead Console

I am in the process of retrofitting a 2010 nav unit into my 2.5i. One thing I would like to investigate is using the overhead microphone instead of the built in one (front upper left corner on HU). I ordered an overhead console which had the microphone and did some investigation. Here are some pics:

 

 

 

Here is what I have found so far:

 

Red: +4.8-13.8Vdc

Black: Ground and audio reference

White / Blue: Audio

 

I measured a 1kHz sine at about 85dBA into the mic and saw +/- 1.2Vpk on the audio wire. The dc input will function at 4.8 - 13.8Vdc. I did not test further outside of that range, but at 4.8v I saw a very slight reduction in peak voltage output on white/blue.

 

From what I can tell there is a dc-dc converter which takes the input and knocks it down to 5.5Vdc. It then feeds the dual opamp that is on there (2732817 JRC). The rest looks like passive components for filtering.

 

I am curious if there are mic inputs on this head unit, and if so does anyone know which? If not, I figure I can attempt to trace the wires on the built in mic back to the preamp and tap in there.

 

Otherwise, for aftermarket integration this thing looks pretty easy. I did find that in my car (2.5i non premium) the harness to the overhead console had the mic wires populated, however I did not test to see if there was power, nor where they went.

 

I hope this is useful.

Interested to see if you can get it to work. I would think the overhead mic would be better than the stock HU location.

I would hope so. My only concern is if there is echo cancellation built into the head unit. If so, the delay from the new microphone position would probably make it a no go. I hope to find out.

I found this thread looking for tips on microphone location. I'll be installing my Pioneer AVIC this weekend. In my Tundra (different AVIC head unit) I placed it in the factory location in the headliner. In my LGT, I've got a moonroof, so I don't believe there's space.

I believe there is. From the pictures I saw in the microfiche (who knows the validity of them...) the difference between the non moonroof and moonroof was the placement of the switches. But again, please feel free to correct me.