The DJI Osmo is a seriously great tool, but it has some major audio issues…
When first I tried to hook up a external Microphone to it I noticed a crazy beep anoying sound on the recordings. So I took the file and feed it through a spectrum analyser and indeed I found a wave at around 16kHz.
To connect the microphone I used a custom cable I built. My Father suggested I should try connecting various resistors between XLR’s hot pin and ground. So I did and I was able to get rid of the beep with a 10 kOhm resistor as you can see here:
Here is the audio of one of the tests.
Hope this helps in case you experience the same problem.