I think it was Scott @scotts who posted it? I had a refernce in my file to the originator of the info but it must have got lost in an edit.
Yeah, at the level I set it I get 3 or 4 LED’s lit. Like you I wanted more. Set your volume to what you normally use then play with that 131071.0f number just before the * (brightness.
If I remember correctly a lower number gets you more LED’s.
It was Scott, found that original thread.
Phat Beat increase VU meter sesitivity - Support - Pimoroni Buccaneers