For a sedan, one sub, 450 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
28.5 Hz
Qts
0.73
Qes
0.795
Qms
9.38
Vas
4.76 ft³
Re (one coil)
3.32 Ω
Sd
128.6 in²
Xmax
0.63″
Vd
81.5 in³ calc.
Mms
226 g calc.
BL
13 T·m calc.
EBP
36 — suits sealed calc.
Sensitivity, 1 W / 1 m
87.9 dB calc.
General
Size
15″
Voice coils
dual 4 Ω
RMS power
450 W
Mounting dimensions
Cutout diameter
13 3/4″
Mounting depth
7 3/8″
Overall diameter
15 1/2″
Magnet diameter
6 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.