I need some help! I was trying use WinISD Pro to model port length for a Stryke AV-15 for my 214L cabinet tuned to 18.5Hz with dual 4" vents to replace my Tempest which is tuned at 15.5Hz using the dual 3" vents. Does WinISD Pro calculate the length of a straight port or a flared port? The reason why I'm asking this is besause I plugged in the port parameters for my original Adire Alignment box using the Tempest driver and 15.4Hz tune on another project folder and got a different port length from Dan Wiggin's recommended lengths. The other thing I noticed is that the port length WinISD Pro calculates actually increases if you increase the number of ports. Is the calulated legnth the TOTAL length of all the ports? How do you calculate for the effect that the polyfil has on the volume of the cabinet? What could I be doing wrong here? P.S. I'm trying to use the 4" ports besause I dont know if I could fit dual 6" ports into my baffle. My internal cabinet height is 26.5 inches so I'll need to find out if they will have enough clearance.