For a sedan, one sub, 700 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
25.6 Hz
Qts
0.53
Qes
0.59
Qms
5.55
Vas
7.13 ft³
Re
1.6 Ω
Sd
≈ 124 in²
Xmax
≈ 0.39″
EBP
43 — suits sealed calc.
Sensitivity, 1 W / 1 m
89.6 dB calc.
General
Size
15″
Voice coils
2 Ω
RMS power
700 W
Mounting dimensions
Cutout diameter
13 3/4″
Mounting depth
7 7/16″
Overall diameter
15 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.