I just wanted to check WinISD agrees with the manufacturer recommended sub box size of 1 cubic foot for my subwoofer, but it seems to be saying I need at least 5!

Has anyone else successfully used WinISD? Mainly my Qms and Qes are way out of whack, it won't let me input what they're supposed to be and uses its own calculated values. I think that's the start of my problems.

The data I have is;

Memphis 15-SC12D4 Shallow mount Subwoofer

Impedance: 4 + 4 Ohms (Dual Coil)
DC Resistance: 1.5 Ohms
Resonant Frequency: 34 Hz
Mechanical Q: 3.32 Qms
Electrical Q: 2.37 Qes
Total Q: 1.38 Qts
Xmax (Linear): 0.24 Inch
Xmax (Mechanical): 0.35 Inch
Sensitivity 2.83 Volts: 88 Db
Vas: 1.2459 Cubic Ft
Moving Mass: 190.13 grams
Motor Strength: 8.2 TM
Voice Coil Diameter: 2 Inch
Minimum Power: 500 Watts
Maximum Power: 1000 Watts
Magnet Weight: 43 Ounces
Mounting Hole: 11.19 Inch
Mounting Depth: 3 Inch
Driver Displacement: 0.296 Cubic Ft