Hard to say, it also depends on how the box is tuned. If it's a competition ported box, tuned to like 50 or 60, then I'd say more spl, but of course it would be bad at low frequencies. If he has a lower tuned box, then it should be louder around the tuning frequency, and a low tuned ported box will have very good low frequency extension. I personally love the sound of a good low tuned ported box.