I'm trying to use the pialign program to get the ideal dimensions for a vented subwoofer based on the 10" dayton titanic woofer.

qts is 0.4 (qd=2.5)
vas is 1.345
fs is 28

from pi allign I get:
enclosure volume of .55
port length of 1.4
port diameter of 1.7

the enclosure size seems way to small (other sources suggest 1.5 cf)

am I doing something wrong?

Thanks