A sealed (closed) box is a 2nd-order high-pass: it rolls off at 12 dB/octave below its system resonance and is forgiving of box-volume error. A ported (bass-reflex) box is 4th-order: it rolls off at 24 dB/octave but gains roughly 3 dB of efficiency and deeper extension near the tuning frequency, at the cost of a larger, fussier cabinet.
Use EBP to pick a starting alignment
The efficiency-bandwidth product, EBP = Fs / Qes, is the quick rule of thumb: EBP above ~100 favors a ported box, below ~50 favors sealed, and 50–100 works either way. It is a starting point, not a verdict — model the actual response before committing.
Tighter bass or more output?
Sealed boxes are preferred when transient accuracy and a compact enclosure matter, or when the driver's Qts is on the higher side. Ported boxes win when maximum low-frequency output and efficiency matter and you can accept the larger box and port-noise considerations.
Whichever you choose, watch cone excursion below tuning (a ported box unloads the driver below Fb) and port air velocity (chuffing). The designer flags both.