Taken off of site> Ported enclosures are distinguished by a vent or duct in the structure. This vent allows the rear sound wave of the woofer to interact with the front sound wave. The coupling of a vent to the air inside the enclosure reinforces the low-frequency response of the subwoofer system and can greatly increase the efficiency. By changing either the length or surface area of the port, the resistance to motion of the column of air within the port changes its resonant characteristics, thus causing the tuning frequency of the enclosure to change.
This is not what happens in a ported enclosure.
You have mentioned elements of the physics involved. But not the function of the physics involved.
A simple point as an example.
No front wave rear wave interaction through the port.
Simply a function of air pressure difference. The front of the woofer cone has essentially an infinity large box it is driving into. Low pressure side, compared to the rear of the cone. Much smaller enclosure side, or high pressure side.
The ports only contribute to the output of the driver very close to their tuning frequency.
No real increase in efficiency, just a tradeoff as to possible bandwidth of frequencies that you can produce.
There is no free lunch. A ported enclosure drops off at the rate of 24 decibels per octave. An octave is a halving or a doubling of frequency. 20 to 40 hertz is an octave. 16 to 32 hertz is an octave.
A sealed enclosure drops off after the box system resonant frequency at 12 decibels per octave. There is appreciable much below the system resonant frequency. And he cone is well behaved as the internal box volume when correctly sized acts like a spring keeping the driver from uncontrolled motion.
A vented enclosure has very little output below the system tuning, and wildly uncontrolled cone motion if you try to drive it much below the tuning frequency. It is simply a little bit more efficient near this tuning frequency than a similarly tuned sealed box. Normally it is about 3 db more efficient near the tuning frequency only.
The tuning frequency is directly linked to three things.
Volume of air the port is sitting in. The woofer enclosure.
Cross sectional surface area of the port.
Length of the port.
For a given tuning frequency versus box size, keeping the area of the cross section constant.
The larger the box size the shorter the length to get the same tuning frequency.
There is much more that could be said.
And I'm not trying to bash you over the head with this.
It's just that from time to time I read things that are worded in such a way that they appear to make sense. There is a degree of technical jargon that looks right.
But that's the end of it.
They don't make sense.