Anyone know what the file type is and it's location in iOS for the speaker attachment? Once mine gets  here later this week, I'd like to be able to play a MP3 (or whatever it is) without having to record it.

Hi there, thank you for reaching out. We really appreciate your Interest using the DJI Product, with regards to your concern Unfortunately there is no way to play an MP3 or Import an Audio file to play from the speaker, you can only able to play audio that is recorded from the DJI GO 4 app. And for the File type of the recorded Audio I will clarify this first from our developer and will reach you back once I have the answer. I hope you understand. Thanks!

My "work around" is to use an audio cable from my computer into my Samsung A7.  Press "Record" on the DJI Pilot app and "Play" on my computer's media player with the audio (MP3) file. I play "Flight of the Valkyries"  along with F-15 Eagle in full afterburner and the P-51 with its supercharger whine.  The latter two really gets people's attention and my friends laughing.