Originally Posted by scottvamp
Problem is on the Ultimax subs one person says they were designed for a sealed box and the next expert says they perform better in a ported box.
Both answers are correct. They were designed for a sealed box, the high Qes/Qts and low EBP makes that obvious. They also will perform better in a ported box, as most drivers will. That's easily seen if you model it both ways in WinISD and let the program go to the default alignment with both options. Sealed gives a 6.5 cu ft box with a 30Hz f3, ported gives a 9.4 cu ft box with a 14Hz f3.
As for port noise, that's almost always the result of ports that are too small in area. That's the case with most commercial subs. They're too small because the correct size results in the cab having to be larger, and that's not what consumers want. The 9.4 cu ft box for the UMax 12 would require about 40 inches area, with a 36 inch duct length, and that's almost another cubic foot right there.