@Dr_Shaggy i am sorry to report to you bro that you have mistakenly bought a SPL sub instead of a SQ sub
You should have done your research before buying the sub. I am sorry for your loss bro, but aab kia ho sakta hay.
It is clearly stated somewhere on this forum that for SQ sub always look for Highest Xmax and Lowest Fs but you overlooked those golden words. Your sub with an Fs of 48hz and Xmax only of 9mm fails both the tests. Sorry bro you failed us 
I wish it was facebook so that i could tag someone to this particular post
