Sorry to bust your bubble' date=' however, a friend of mine had two dd z 15s, swapped them with the level 5's and gained 0.5 db. And the dc neos are known to be 0.7 - 1 db louder than the level 5's. And I know, because I also use to run the DDZ series subs. The ddZ series are great but, they cant hold a candle to the DC neo subs. Sorry!!