Audio Systems: MTX T9512-44 VS JL12W7, watt rms, audible difference

Question
Out of those 2 wich would be louder.
My current setup is one T9512-44 with a 1500 watt rms amp

Going to run 2 subs now but im not sure wich out of the 2 would work best in terms of loudness
And yes they will be in a custom box tuned to probably 32-35 Hz  

Thanks in advance

Answer
The MTX sensitivity is: 84.7db
The JL sensitivity is: 86.2db

Therefore the JL is louder at the test frequency by 1.5db.  This is just enough to hear an audible difference.  It takes about 2db difference to hear a distinct and unmistakable difference in sound pressure level by the human ear.  It takes about 9bb difference in level for one source to sound about twice as loud as the other.  3db is the 2/1 power difference; that is it takes twice the power to increase the output level of a speaker by 3db.  It takes 9 times the power input to make is sound to the ear like it is two times louder!

The JL will take about 25% less power to sound the same level as the MTX; probably not much difference.  I would choose the driver on the basis of sound quality and reputation for reliability.  Both come from good stock.

Hope this helps.
cleggsan