I have to agree with PhilM.
Very true the ported enclosures are larger, can provide more "volume" with the same woofer, can be peaky, can have bad frequency response, but all these are factors of box design. Typically not the fault of the woofer, unless the manufacturer wants more sales and "claims" the woofer works in a ported enclosure. There are several software programs that can verify this mathmatically. Physics don't lie.
Sealed enclosures are far easier to build and smaller. Woofers tend to sound "tighter" in a sealed enclosure because the rear wave of the woofer is not heard since it is sealed in the enclosure.
The freeair stuff is out there and can serve as a low bass re-enforcement, but can never replace an enclosure. The volume just will not be there. I also haven't seen a freeair woofer that could take a lot of wattage.
As I said I have used both in my car and just happen to have a ported enclosure in it now. The next box will be sealed since the woofers I looking at using are specifically for a sealed enclosure. Just means I'll need more woofers to get the same volume.
Something not mentioned is the amp. The more damping factor the amp has the better it can control the woofer, thereby increasing the "tightness" sound. My ported enclosures have all sounded like sealed enclosures since my sub amp has a ton of damping factor and has been modified to have a custom feedback circuit
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John