To have some sound in the video clips I downloaded a recording app to my smartphone (a Sony Xperia Z2) that is able to continue recording although the app is in the background when I have the DJI Vision app running. I found having the same audio I hear when I'm flying also in the video clip quite cool and a nice alternative to always using post-added music. However the sound quality wasn't top notch and I got some crackling noise every now and then. Not sure if it was caused by the wind or some other interference. Because of this I thought I would try to find a better external microphone compatible with my smartphone and I especially looked at Sony's STM10 but not sure how good it is compared to the built in mic. I also checked out some microphones from a company called Edutige which seems to have some good alternatives but not sure if any of their microphones would work with my Sony Xperia Z2. Anyone else in here using an extremal mic for a Sony Xperia Z2 with good results?