For a sedan, one sub, 3,000 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
27.1 Hz
Qts
0.31
Qes
0.34
Qms
3.8
Vas
4.80 ft³
Re (one coil)
0.85 Ω
Sd
179.8 in²
Xmax
≈ 0.39″
Mms
483 g calc.
BL
14.3 T·m calc.
EBP
80 — sealed or ported calc.
Sensitivity, 1 W / 1 m
91 dB calc.
General
Size
18″
Voice coils
dual 1 Ω
RMS power
3,000 W
Mounting dimensions
Cutout diameter
≈ 16 9/16″
Mounting depth
≈ 8 1/4″
“≈” 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.