What exactly does db sensitivity mean? My front speakers are cerwin-vega vs 120 rated at 97db sen my rears are cerwin-vega E-208's rated at 92db and my cv sub is 50-150HZ @18db/octive can someone break this down where I can understand it. I also have my subs freq turned all the way down to 40. 80 is half way 120 is all the way is ok. Thanks.