as mad as everyone will be for saying this but that is the power rating for a single sony. i run 2 sony 12" and it is equally as loud as my cousing dual alpine r 12s
To go along with BlackSheep...
SPL is a matter of a multitude of things...
Box Size, Box Layout, Box Type, Speaker Placement, Vehicle Acoustics, and many other things constitute "loudness".
And, what if this enclosure is destined for an SQ application? LOUDNESS is a definition given by the individual listening, not an established baseline that can be measured.
I personally think my truck isn't "LOUD" enough, but my wife can't stand it if I even have the subwoofer turned on.
Now... Can two 12" Sony Subwoofers sound Louder than and reach higher SPL ratings than two 12" Alpines... SURE! But, it all depends on the applications. I just recenetly built a Dual 12" Sony enclosure that was 4th order bandpass with 165 watts to each woofer. And, I can say, that thing got LOW. I mean, REALLY LOW. But, it was in a little Passat. Take that same box and put it in an Excursion, and you probably wouldn't get the same effect due to the internal vehicle volume variance.
End all statement...
Don't jump in a thread with a simple statement that doesn't really continue or solve the topic.