A ported enclosure can be 3dB more efficient at the same size or play a quarter octave lower at the same efficiency.
The same driver excursion will net you perhaps an extra 1/3 octave of extension with a ported speaker.
You'll have higher excursion limited output in the bottom of a ported design's pass-band so you can use smaller + less expensive drivers.
Distortion will also be lower in the bottom of the speaker's pass-band with the port because of the reduced excursion.
Ported enclosure+driver combinations have four poles in their high-pass function for an eventual 24dB/octave roll-off function while sealed ones have just two for 12dB/octave. With sufficiently shallow roll-off room gain (12dB/octave in an infinitely rigid room below its fundamental resonance at 1130 / 2 / the longest dimension) can keep the speaker flat below its roll-off.
Ported enclosures do not load the driver once you get below the port tune, with excursion increasing to what it would be in free air. Where too much low frequency energy is present below the speaker's pass-band you'll have distortion (including midrange IM distortion on 2-way speakers) and may even run the drivers into their mechanical limits resulting in damage (some very nice drivers will bottom the voice coils on the back plate). For a given input level sealed speaker excursion remains constant with decreasing frequency.
The same driver excursion will net you perhaps an extra 1/3 octave of extension with a ported speaker.
You'll have higher excursion limited output in the bottom of a ported design's pass-band so you can use smaller + less expensive drivers.
Distortion will also be lower in the bottom of the speaker's pass-band with the port because of the reduced excursion.
Ported enclosure+driver combinations have four poles in their high-pass function for an eventual 24dB/octave roll-off function while sealed ones have just two for 12dB/octave. With sufficiently shallow roll-off room gain (12dB/octave in an infinitely rigid room below its fundamental resonance at 1130 / 2 / the longest dimension) can keep the speaker flat below its roll-off.
Ported enclosures do not load the driver once you get below the port tune, with excursion increasing to what it would be in free air. Where too much low frequency energy is present below the speaker's pass-band you'll have distortion (including midrange IM distortion on 2-way speakers) and may even run the drivers into their mechanical limits resulting in damage (some very nice drivers will bottom the voice coils on the back plate). For a given input level sealed speaker excursion remains constant with decreasing frequency.