ported box

Hmmm.

You have an awful lot of reading to do.

Generally, a ported box produces the most output around the tuning frequency... above the tuning frequency the box acts more and more sealed... below the tuning frequency the woofer begins to act like it isn't enclosed at all... generally a steep volume roll off and reallly bad sound.  Ported boxes are generally peakier than their sealed brethern, but if you have a program like WinISD, you can often design something that is quite flat...   for example I got the *best* response from my JL 13W6 using a port tuned to about 28hz... way better than any of the half-dozen or so sealed boxes I built for it.

The port and the cone work together to produce the sound you hear when you port a box.. the rear of the speaker cone also produces sound and the port sort of channels that sound back into the system..instead of dissipating inside the box.

http://www.jlaudio.com/tutorials/magic/index.html

http://www.jlaudio.com/tutorials/ports/index.html

More members will prolly (or already have) post up with lotsa other stuff to read which is way headier than the stuff on the JL site... but its a good place to start.

Read up a bit then post back with more specific questions.