Focal K2 Power 40 KX (DVC 2+2 ohm)

16″ subwoofer · dual 2 Ω · 500 W RMS

Fs 34.6 HzQts 0.82Vas 2.29 ft³Xmax 0.43″

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 volume	2.83 ft³ (80 L)
Qtc	1.10
Fc	47 Hz
F3 (−3 dB, no cabin gain)	36 Hz
Example box (outside)	31 1/2″ × 18 1/2″ × 11 1/2″

Open sealed box in designer

Ported

Net volume	4.84 ft³ (137 L)
Tuning (Fb)	33 Hz
Port	slot 2 3/16 × 17 1/16″, 13 3/4″ long
Port velocity at 500 W	66 ft/s
F3 (−3 dB, no cabin gain)	27 Hz
Example box (outside)	31 1/2″ × 18 1/2″ × 19 1/2″

Open ported box in designer

Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs	34.6 Hz
Qts	0.82
Qes	0.97
Qms	5.3
Vas	2.29 ft³
Re (one coil)	2.1 Ω
Sd	124.7 in²
Xmax	0.43″
Vd	54 in³ calc.
Mms	299 g calc.
BL	11.9 T·m calc.
EBP	36 — suits sealed calc.
Sensitivity, 1 W / 1 m	86.4 dB calc.

General

Size	16″
Voice coils	dual 2 Ω
RMS power	500 W

Mounting dimensions

Cutout diameter	≈ 14 7/16″
Mounting depth	8 1/8″
Overall diameter	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.