How do you make a system really bump? ?
I'll tell ya how..
First understand SPL
it is measured in db and 1db is the smallest volume change the human ear can hear. 10db is "twice as loud" and when power is doubled it is equal to 3db. likewise doubling cone surface area is 3db. and a properly made box can easily make a 3db difference over a enclosure that is poorly made.
Now speakers have a efficiency rating, it is a measure of db @ 1 watt @ 1 meter. so the higher the number the louder it is.
often times a sub will put out much more volume in a ported enclosure than a sealed enclosure.
so with that information here is a example..
System A - 1000 watts RMS driving a single 12" 87db sub with a off the shelf sealed sub enclosure.
System B - 250 watts RMS driving 2 x 12" 90db subs with a custom made ported box.
these systems would cost about the same, but the second would be louder... even with a mere 250 watts. take this system x2 and now the first needs electrical upgrades (~$400) but the second works with a stock alternator.