For a sedan, one sub, 250 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
42 Hz
Qts
0.58
Qes
0.6
Qms
17.4
Vas
0.83 ft³
Re (one coil)
1.8 Ω
Sd
54.3 in²
Xmax
0.39″
Vd
21.4 in³ calc.
Mms
106 g calc.
BL
9.2 T·m calc.
EBP
70 — sealed or ported calc.
Sensitivity, 1 W / 1 m
86.6 dB calc.
General
Size
10″
Voice coils
dual 2 Ω
RMS power
250 W
Mounting dimensions
Cutout diameter
9 1/16″
Mounting depth
3 1/4″
Overall diameter
10 1/4″
Magnet diameter
6 1/8″
“≈” 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.