i ended up picking up one of these and after watching my first videos recorded with this thing, you couldnt hear anything but buzzing, rattles, and noise.
i had to tape a business card (card stock thickness) to the back of the camera so it didnt rattle against the GPS unit, which quieted down the bulk of the noise you could hear in the video.
then i had some other rattles picked up in the video, turns out the CPL filter lens was not "tight" in the holder. had to add 2 thickness of scotch tape to both sides of the channel where the CPL lens slides into. then trimmed off excess with xacto knife and fixed that rattle.
now that all the rattling noise in the audio had (mostly) stopped i noticed that the mic level was kind of low. the dash cam could barley pick up my voice when driving but couldnt make out what i was saying at all, it couldnt pick up the passenger voice at all even though she was actually about a foot closer to the camera than i was. then found this thread and decided to open up the unit. mic was facing INSIDE the unit, so i rotated it 180* and so it now faces the to the outside of the unit where there are some vent holes. audio is now 10x better, much more clear, you can make out what is being said in the cabin now, you can hear radio clearly, you can even hear conversation if someone is standing immediately outside the car and windows down (like a LEO for example). you can even hear click click click of the turn signal.
while i was in there i spread the capacitors apart a bit, and bent one upwards more out of the way, tying to be preemptive of any new rattles that might be picked up in audio. put it all back together and could still hear some squeaking in the audio during certain times. found out by pressing on the back side of the camera (where gps attaches) in the middle, the top plastic casing would squeak when sliding against the side of the case. opened it back up and noticed there are 2 little notches on the side. put some cloth tape on those little notches and put it back together.. it still moves ever so slightly when pressed, but doesnt squeak anymore.
now videos sound like they should..
FWIW, i put this cam in a mustang GT, suspension is kind of stiff, sits low to the ground, you definitely feel the road while driving. so someone mounting this in say a Cadillac or Lincoln, even an SUV may not have to deal with the same issues i had as their ride is probably not as harsh as mine can be
next step will be to replace oem battery with AGM battery and add hardwire kit.
