Lets clear this up.
BIG does not = loud db
MORE does not = loud db
EXCRUSION does not = loud db
CONE AREA does not = loud db
BIG WATTS does not = loud db

Of cause you guys know what I mean as in overkill for instance in our town we had a db drag there where some nice setups one had 4 hi powered 15” subs they went off they got some nice cone movement but the highest reading of the day (the winner) was high 140's I think it was 147 or 149 it wasn’t too long ago I cant remember I didn’t stay until the end it was a dull drag but anyway too bad if I rocked up with that dd audio 10” setup and wiped their face clean

zinger002 said “of course 2 18's are gonna be crazy loud... dosent even matter what brand... if p-p excursion is the same and cone size is the same... displacement is the same... the only reason they are loud is cuse they are square...”
square has little to do with it. in theory if has the same excursion and cone area it will be as loud but in practice it isn’t true the specifications do matter you will not put out a high db reading out of a $50 sub it will die first.

Chieftorius said “Theres a guy in the US using a single jackhammer in a wall for bassrace and is doing around 147. Congratulations, you just wasted how many thousands of dollars?” you are 100% correct but if it was setup correctly it can put out some nice readings.

Some spl vans have 2 solo x 18” and they put out in the mid 150db and some run 100,000watts and like 10x 10” subs and barely reach in the high 160db but take dd audio themselves they went to the extreme to bring to our attention that wattage, size, excursion don’t really matter and put out 169db out of a single 10” its all about the setup and tuning.

I have done some exclusive testing and experiments and I think its true but some will disagree, that’s my though on this matter.