naw man. I was talking to that dumb@ss 80 dude. Still have not seen him post the port size he came up with. Or maybe he doesn't have the mental capabilities to figure it out.
Mrcabinetry-
You seem like an intellegant fellow and you did not come off like a smart @ss like 80 so that is why that comment was directed towards him. No offense to you, all towards 80.
NO problem man, I saw the mr. there and I thought the comment was directed towards myself.
As for the matter at hand, for what it worth, you don't necessarily need to know what subwoofer is to design a ported enclosure since the volume of the enclosure, port area and port lenght determine the tuning frequency of the port.
It helps to know what sub is being used so so it can be determined in the sub being used given the wattage being applied to the subwoofer given the port size and port tuning frequency is going to create port noise using enclosure design program such as Bass Box Pro 6 or WINisd.
There are calculators at various sites that allow to you put in certain parameters that will provide you with such things as the vent mach of given port size and tuning frequency based on the power input.
And since whomever is only using a subwoofer that is rated 250 rms - 500 max pe givne the size of the enclosure and port size...... yeah, he could get away with using one port at the size stated, however two port at the size I stated would reduce the compression buildup at the port opening inside the enclosure allowing for better bass response and performance since twice as much air would be moving.
However, other factors contribute to the design of the enclosure as well, namely displacements for all the various other elements involved in enclosure designing.