big port vs small port area

[Bluebrindle]

I,m trying to determine what makes a good size port which works well.

In the uk where i,m from its a given that 10" per cube is the way to go. yes the spl boys may use larger ports but 10" per cube is about where its at for streetbass. i have heard boxes with very small port area like 6" per cube get very very loud (148 db @32 ish hz using 1 orion hcca 15 ) , look at meades car, i,m not 100% sure but that cant have more than 8" per cube just by me looking at it.

Now over in the states you guys always recomend 12-16" per cube.

why is this? i,m building a box for 2 dc lvl5 18's

i have a sundown 3500 for each and have 14.4 cu ft before displacement.

if i do 10" per cube i have iirc 6 cuft per sub , if i do 12" i have iirc 5.75 per sub.

so whats best? i,m trying to get a term lab to test myself, at which time i can make different size ports but would like sone input.

btw this is no spl car, its just a (hopefully) loud street car.