My sub when i had setting at +12DB on HU it was insane i turned it down to +2 its a bit better would it be pushing to much into the sub at +12 i doubt i should have the setttings at max right?
you can have it set a 12 but than you wont be able to turn your volume up all the way or your amp will start to clip.
What these Bass Boosts do is Boost a certain low end freq. So when that freq is played its a stronger signal going to the amp than the other signals. So your volume could be up and be playing fine (not clipping) but then when a certain freq bass note (or band of notes) hits, the signal going to the input of the amp is much higher than normal, therefore the output will be higher than normal as well, so the amp will clip the signal.
All in all, you shouldnt need to use the bass boost. More times than not it gets abused bc people still want to crank the volume. If your bass is lacking, get louder deeper subs with more power, dont push your equipment beyond its limits.