I have noticed that some Videos posted carry the sound of their Phantom. Is there a built in Mic that I haven't found yet or this this an extra purchased?
The phantom Vision 2 + or its predecessor does not have a built in mic. Go Pro cameras record sound as they have a built in mic. Most people do not want to record the sound of the 'drone' - Because I wanted to record sound and still wanted the convenience of having a Go Pro on a Vision 2+ I converted a Vision 2+ by removing its original DJI camera and installing a Go Pro Hero 4 with gimbal. Go Pro's have fisheye but this can be eliminated using a aftermarket lens..
Funnily enough, I tend to edit my videos so that, from just before I start the props, through to them spooling up and the bird taking flight, the sound slowly fades out, and music slowly fades in. I then end the videos in the reverse, with the sound of the props slowly fading back in as the music fades out, and then stop the video just as the props cut out totally.
So I like the sound being recorded, but don't use a lot of it.
There is the easy way (expensive solution by dronexpert) and the harder way (cheap solution by the R&D enthusiasts at the RC forum ). You make your choice depending on your technical skills
I chose to do the easy way as I wanted a quick way to swap back the original DJI camera