quackhead 10+ year member
HUH?
the pro-box you had was tuned higher, somewhere around 45hz, which incidentally happens to be where most "bass boost" features are tuned, combined with cabin gains, make them very loud and boomy...as you obviously figured out. The 30-31hz tune will flatten the response down to the lower octaves and decrease the booming effect, while allowing for much lower frequency extension.