Its not hard for a single 10" to be louder than your 4-8's, will it move the same amount of air maybe yes or maybe no. What tuning and any other information to help you make the decision on the right sub. I had 3-12"s kicker cvx underpowered and now I have one sundown zv.1 15" underpowered and the 15" is louder, it doesnt move the same amount of air but it gets louder though. Hope that helps. something to think about. thanks Jay-cee