i have the onkyo 770 and the specs states that the sub is a 10" 220watt powered sub. On the back of the sub it says max output 150watts (or something like that) I was wondering if that is how everyone elses is because i know that onkyo makes a 150watt sub. I just want to make sure i got the right thing, and if so why does it say 150watt on the back?