For a sedan, one sub, 300 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
31.6 Hz
Qts
0.73
Qes
0.766
Qms
17.3
Vas
2.68 ft³
Re
3.82 Ω
Sd
82.3 in²
Xmax
0.52″
Vd
42.8 in³ calc.
Mms
133 g calc.
BL
11.5 T·m calc.
EBP
41 — suits sealed calc.
Sensitivity, 1 W / 1 m
87 dB calc.
General
Size
12″
Voice coils
4 Ω
RMS power
300 W
Mounting dimensions
Cutout diameter
11″
Mounting depth
5 3/8″
“≈” 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.