Kenwood KFC-XW1241HP

12″ subwoofer · 4 Ω · 500 W RMS

Fs 20.5 HzQts 0.27Vas 4.03 ft³Xmax 0.31″

Recommended box

For a sedan, one sub, 500 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 volume0.71 ft³ (20 L)
Qtc0.69
Fc53 Hz
F3 (−3 dB, no cabin gain)58 Hz
Example box (outside)14 3/16″ × 14 3/16″ × 10 1/16″
Open sealed box in designer

Ported

Net volume1.45 ft³ (41 L)
Tuning (Fb)31 Hz
Portslot 1 9/16 × 14 5/16″, 39 7/16″ long
Port velocity at 500 W55 ft/s
F3 (−3 dB, no cabin gain)33 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 10 1/2″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs20.5 Hz
Qts0.27
Qes0.281
Qms6
Vas4.03 ft³
Re≈ 3.4 Ω
Sd≈ 76 in²
Xmax0.31″
EBP73 — sealed or ported calc.
Sensitivity, 1 W / 1 m87.4 dB calc.

General

Size12″
Voice coils4 Ω
RMS power500 W

Mounting dimensions

Ø≈ 12 5/16″cutout ≈ Ø11 1/8″mounting depth 5 13/16″magnet Ø≈ 7 3/16″
Cutout diameter≈ 11 1/8″
Mounting depth5 13/16″

Only Qts is published — Qms assumed to be 6 and Qes calculated (barely affects box design).

“≈” 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 Kenwood 12″ models