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
28.3 Hz
Qts
0.42
Qes
0.44
Qms
12.45
Vas
3.42 ft³
Re (one coil)
1.88 Ω
Sd
125.4 in²
Xmax
0.57″
Vd
71.6 in³ calc.
Mms
303 g calc.
BL
15.2 T·m calc.
EBP
64 — sealed or ported calc.
Sensitivity, 1 W / 1 m
89 dB calc.
General
Size
15″
Voice coils
dual 2 Ω
RMS power
—
Mounting dimensions
Cutout diameter
≈ 14″
Mounting depth
≈ 7 1/16″
“≈” 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.