Alpine SWR-8D2 (Type-R)

8″ subwoofer · dual 2 Ω · 350 W RMS

Fs 40 HzQts 0.50Vas 0.37 ft³Xmax 0.47″

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 volume0.28 ft³ (8 L)
Qtc0.76
Fc61 Hz
F3 (−3 dB, no cabin gain)60 Hz
Example box (outside)10 1/4″ × 10 1/4″ × 8 1/2″
Open sealed box in designer

Ported

Net volume0.78 ft³ (22 L)
Tuning (Fb)34 Hz
Portround port Ø2 1/2″, 13″ long
Port velocity at 350 W188 ft/s
F3 (−3 dB, no cabin gain)31 Hz
Example box (outside)20 13/16″ × 15 3/4″ × 6 7/8″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs40 Hz
Qts0.50
Qes0.54
Qms7.2
Vas0.37 ft³
Re (one coil)1.85 Ω
Sd31.2 in²
Xmax0.47″
Vd14.7 in³ calc.
Mms86 g calc.
BL8.6 T·m calc.
EBP74 — sealed or ported calc.
Sensitivity, 1 W / 1 m83 dB calc.

General

Size8″
Voice coilsdual 2 Ω
RMS power350 W

Mounting dimensions

Ø8 7/16″cutout Ø6 7/8″mounting depth 4 1/2″magnet Ø≈ 4 1/2″
Cutout diameter6 7/8″
Mounting depth4 1/2″
Overall diameter8 7/16″

“≈” 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