really? well this is wut i think that if u get a large sealed box and a ported one tuned at 27hz and play some rap
they will both reach the same lowness just that the ported one will have a little more spl around 27hz
because lets say the songs bass only reaches down to only 25hz so below that it doesnt really matter.
but if u have a song that reaches all the way down to 15hz(i doubt there is one) the sealed will hit lower because sealed can reach lower all the way down to the subs Fs(if its as low as 15hz) and the ported will have a steep dropoff at 27hz so it wont hit as low