For a sedan, one sub, 600 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
27.6 Hz
Qts
0.53
Qes
0.553
Qms
10.69
Vas
2.13 ft³
Re
3.51 Ω
Sd
98.3 in²
Xmax
0.43″
Vd
42.6 in³ calc.
Mms
314 g calc.
BL
18.6 T·m calc.
EBP
50 — suits sealed calc.
Sensitivity, 1 W / 1 m
85.6 dB calc.
General
Size
13.5″
Voice coils
4 Ω
RMS power
600 W
Mounting dimensions
Cutout diameter
12 1/2″
Mounting depth
2 5/8″
Overall diameter
14 3/16″
Magnet diameter
6 3/4″
“≈” 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.