Kicx STC-380

15″ subwoofer · 4 Ω · 350 W RMS

Fs 22 HzQts 0.67Vas 3.12 ft³Xmax 0.26″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 350 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

Net volume2.83 ft³ (80 L)
Qtc0.97
Fc32 Hz
F3 (−3 dB, no cabin gain)27 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 11 3/4″
Open sealed box in designer

Ported

Net volume4.80 ft³ (136 L)
Tuning (Fb)25 Hz
Portslot 1 9/16 × 16 11/16″, 19 3/16″ long
Port velocity at 350 W65 ft/s
F3 (−3 dB, no cabin gain)21 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 19 7/8″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs22 Hz
Qts0.67
Qes0.801
Qms4.01
Vas3.12 ft³
Re≈ 3.4 Ω
Sd≈ 124 in²
Xmax0.26″
EBP27 — suits sealed calc.
Sensitivity, 1 W / 1 m82.7 dB calc.

General

Size15″
Voice coils4 Ω
RMS power350 W

Mounting dimensions

Ø≈ 15 3/16″cutout ≈ Ø14″mounting depth 5 7/8″magnet Ø≈ 9 1/16″
Cutout diameter≈ 14″
Mounting depth5 7/8″

“≈” 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.

Data sources

Other Kicx 15″ models