Alpine S2-W8D4

8″ subwoofer · dual 4 Ω · 300 W RMS

Fs 47.9 HzQts 0.66Vas 0.26 ft³Xmax 0.51″

Recommended box

For a sedan, one sub, 300 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 volume0.53 ft³ (15 L)
Qtc0.81
Fc59 Hz
F3 (−3 dB, no cabin gain)54 Hz
Example box (outside)9 13/16″ × 9 13/16″ × 15 3/16″
Open sealed box in designer

Ported

Net volume1.17 ft³ (33 L)
Tuning (Fb)33 Hz
Port2 round ports Ø3″, 27 7/16″ long
Port velocity at 300 W79 ft/s
F3 (−3 dB, no cabin gain)29 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 7 5/16″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs47.9 Hz
Qts0.66
Qes0.74
Qms5.9
Vas0.26 ft³
Re (one coil)3.6 Ω
Sd30.1 in²
Xmax0.51″
Vd15.4 in³ calc.
Mms78 g calc.
BL10.7 T·m calc.
EBP65 — sealed or ported calc.
Sensitivity, 1 W / 1 m82.5 dB calc.

General

Size8″
Voice coilsdual 4 Ω
RMS power300 W

Mounting dimensions

Ø8 9/16″cutout Ø6 7/8″mounting depth 3 11/16″magnet Ø≈ 4 7/16″
Cutout diameter6 7/8″
Mounting depth3 11/16″
Overall diameter8 9/16″

“≈” 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.

Data sources

Other Alpine 8″ models