For a sedan, one sub, 1,500 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
34 Hz
Qts
0.94
Qes
1.044
Qms
9
Vas
3.14 ft³
Re (one coil)
≈ 0.85 Ω
Sd
182.6 in²
Xmax
0.93″
Vd
168.9 in³ calc.
Mms
483 g calc.
BL
9.2 T·m calc.
EBP
33 — suits sealed calc.
Sensitivity, 1 W / 1 m
87.3 dB calc.
General
Size
18″
Voice coils
dual 1 Ω
RMS power
1,500 W
Mounting dimensions
Cutout diameter
16 3/4″
Mounting depth
9″
Overall diameter
18 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.