For a sedan, one sub, 750 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 Hz
Qts
0.66
Qes
0.768
Qms
4.7
Vas
4.95 ft³
Re (one coil)
3.2 Ω
Sd
139.4 in²
Xmax
0.66″
Vd
92.2 in³ calc.
Mms
284 g calc.
BL
14.2 T·m calc.
EBP
35 — suits sealed calc.
Sensitivity, 1 W / 1 m
87.6 dB calc.
General
Size
15″
Voice coils
dual 4 Ω
RMS power
750 W
Mounting dimensions
Cutout diameter
14 1/16″
Mounting depth
8 5/16″
Overall diameter
15 1/2″
“≈” 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.