I was able to get the video to play... Its a "whistling" noise, but more like a whoopie cushion letting air out slowly... Hard to describe but definitely coming from the air hole in the durso cap.Can’t see the video but the way I see it only way to make the water in overflow lower is slowing the flow from return pump. Making the pipe taller won’t do anything for noise, unless the noise you’re getting is splashing noise from water falling lower into overflow.
I tried durso, Maggie mufflers, and could never get the noise down. Full siphon is the only way to go in my book.