These wings make such an amazing noise as they cut through the air. You need to hang a boom mic from the risers with a giant wind muff on it to capture the sound it makes for the first person videos.
That is 100% not allowed on Planfait but good on you for picking a late evening with not many people around. I hope you had some communiation on the radio with the filming guy to make sure nobody comes onto take off.
Yes, it is real sound :) the sound is effect of going with some speed through the air so i think it is make by wing, harness, lines and also pilot's body :)