Scientific Explanation Of The 'Roar"

[MisterE]

Good day fellow AP'ers.

About a year ago while on Reddit I read a post that contained a scientific explanation of the 'Roar' 'Ringing' 'Vibration' that is common to AP experiences. As hard as I've tried I've been unable to find the post that referenced this scientific explanation. I'm hoping that someone here has any link to any scientific explanation of this physical effect. I know that it exists somewhere. Just need a bit of help from the experienced AP'ers.

Oh! And I am experienced.

Mark