For a sedan, one sub, 500 W. It’s the same math as the designer’s step-by-step mode, where you can fit the box to your space, vehicle and amp and get plans, a cut sheet and DXF.
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain
Thiele/Small parameters
Fs
28 Hz
Qts
0.50
Qes
0.534
Qms
7.68
Vas
2.81 ft³
Re
1.66 Ω
Sd
80.6 in²
Xmax
0.51″
Vd
41.3 in³ calc.
Mms
156 g calc.
BL
9.2 T·m calc.
EBP
52 — sealed or ported calc.
Sensitivity, 1 W / 1 m
87.1 dB calc.
General
Size
12″
Voice coils
2 Ω
RMS power
500 W
Mounting dimensions
Cutout diameter
11 1/16″
Mounting depth
6 5/8″
Overall diameter
12 1/2″
Magnet diameter
5 1/2″
“≈” means the value isn’t in the spec sheet and a typical value for the size is used; “calc.” means it’s calculated from the published parameters. Check the manufacturer’s spec sheet before you build.