X5 and E39 microphone?

[AV8R4AA]

I installed in both rides a Aux input cord. Loving the tunes and the phone.
Both vehicles the phone works fine. Hearing and talking works fine.
My question is where is the pickup microphone on the 5 series?
I took down the overhead panel on the E39. There appears to be a slotted
Cover that looks like there should be a microphone inside.
There is no microphone in there. (Not sure on the X5) my voice is being picked up by some microphone. Where is it?