I would disagree with your belief that speaker port shapes do not 
matter. It matters just as much as the internal shape of the loudspeaker 
enclosure does. 
        The whole theory of porting is to allow for the evacuation of moving 
air from the rear half of the moving cone, and to "tune" that moving 
air/sound to a specific frequency while doing so, and reinforcing lower bass 
signals. A ports diameter in relation to its' length has just as much to do 
with the tuning process as does anything else in a loudspeaker design. Ports 
are also subject to the same problems as enclosures are, such as standing 
waves.
        Port placement is also extremely important. Too close to an internal 
speaker wall and the port looses efficiency and tuning. Set centered on the 
box causes a boomy, "goofy" sound that is very inaccurate and just as useless 
except for car audio. From what I have seen this goofy, boomy sound is the 
desired effect in car audio.
Cheers, John
 
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