First close your windows, shut the HVAC FAN off or at least to the low setting
That is what it reads in your Owners Manual
sometimes that is not enough, you have to project your voice to the top of the rear view mirror, ( they could not have picked a worse spot to place it )
With the windows partially open, it causes a cross wind from side to side. With the Fan on High, it also causes a upwards draft.
A better place would be tucked in behind the drivers door post, close against the windshield.
I understand that the microphone is now up in the headliner on the newer Rams
... my thought has been since 2009, that they should have placed the microphone in the Overhead Console, along both sides. It would be above & just a bit in front of the drivers right ear & another on the passenger side.
On my 2009 & currently in my 2016 Ram, i have an auxiliary speaker for my CB radio up in the overhead console, at the rear sloping edge
You may be able to spot the round shadow area, at the back center of the overhead console
The shadowy area was caused by scraping the insulation carefully away from the headliner