When does the eq curving or loudness features go away in the HU when turning the level up?

Anyone know, or have a reference to a measurement?

 

Forgot to add, this is an 07-Type S, Stock Navi.

 

honestly, i don't think it stops. its been designed from the factory as an "idiot proof" system. that meaning you can leave it cranked all day long and never hurt it. in order to make it survive anything you throw at it, they generally add more equalization the higher you turn it up. thats why it feels more bassy and throaty at lower volumes then dies off and gets less bassy as you turn it up.