For a sedan, one sub, 200 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
33.2 Hz
Qts
0.70
Qes
0.84
Qms
4.37
Vas
2.33 ft³
Re
1.74 Ω
Sd
83.6 in²
Xmax
0.37″
Vd
30.9 in³ calc.
Mms
143 g calc.
BL
7.9 T·m calc.
EBP
40 — suits sealed calc.
Sensitivity, 1 W / 1 m
86.6 dB calc.
General
Size
12″
Voice coils
2 Ω
RMS power
200 W
Mounting dimensions
Cutout diameter
11″
Mounting depth
5 3/8″
Overall diameter
12 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.