I didn't have someone to hold my phone nor did I have a GoPro, but I wanted to try and capture the sound of my custom Audi A5 exhaust from the inside of the cabin. Try not to stare at the screen,(you might get a seizure), and just listen to the sound. It sounds more true and accurate if you listen to it from something other than your phone speakers! The clinking noise is just my keychain rattling.
