Focal Slatefiber SUB 20 SF (SVC 4 ohm)

8″ subwoofer · 4 Ω · 200 W RMS

Fs 36 HzQts 0.38Vas 0.42 ft³Xmax 0.39″

Recommended box

For a sedan, one sub, 200 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 volume0.28 ft³ (8 L)
Qtc0.60
Fc57 Hz
F3 (−3 dB, no cabin gain)72 Hz
Example box (outside)11″ × 11″ × 7 3/8″
Open sealed box in designer

Ported

Net volume0.60 ft³ (17 L)
Tuning (Fb)38 Hz
Portround port Ø2 1/2″, 13 1/2″ long
Port velocity at 200 W130 ft/s
F3 (−3 dB, no cabin gain)35 Hz
Example box (outside)19 9/16″ × 15 3/4″ × 6 1/8″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs36 Hz
Qts0.38
Qes0.42
Qms3.8
Vas0.42 ft³
Re2.8 Ω
Sd31.3 in²
Xmax0.39″
Vd12.3 in³ calc.
Mms94 g calc.
BL11.9 T·m calc.
EBP86 — sealed or ported calc.
Sensitivity, 1 W / 1 m83.3 dB calc.

General

Size8″
Voice coils4 Ω
RMS power200 W

Mounting dimensions

Ø9 1/16″cutout Ø7 7/8″mounting depth 3 9/16″magnet Ø5 1/8″
Cutout diameter7 7/8″
Mounting depth3 9/16″
Overall diameter9 1/16″
Magnet diameter5 1/8″

“≈” 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 Focal 8″ models