Alpine SWR-843D (Type-R)

8″ subwoofer · dual 4 Ω · 350 W RMS

Fs 40 HzQts 0.56Vas 0.42 ft³Xmax 0.55″

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 volume0.39 ft³ (11 L)
Qtc0.80
Fc58 Hz
F3 (−3 dB, no cabin gain)54 Hz
Example box (outside)10 1/4″ × 10 1/4″ × 10 13/16″
Open sealed box in designer

Ported

Net volume1.17 ft³ (33 L)
Tuning (Fb)32 Hz
Port2 round ports Ø2 1/2″, 20 1/2″ long
Port velocity at 350 W113 ft/s
F3 (−3 dB, no cabin gain)28 Hz
Example box (outside)30 3/8″ × 15 3/4″ × 7 1/16″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs40 Hz
Qts0.56
Qes0.6
Qms7.5
Vas0.42 ft³
Re (one coil)3.7 Ω
Sd31.2 in²
Xmax0.55″
Vd17.2 in³ calc.
Mms75 g calc.
BL10.8 T·m calc.
EBP67 — sealed or ported calc.
Sensitivity, 1 W / 1 m83.1 dB calc.

General

Size8″
Voice coilsdual 4 Ω
RMS power350 W

Mounting dimensions

Ø8 7/16″cutout Ø6 15/16″mounting depth 4 1/2″magnet Ø≈ 4 1/2″
Cutout diameter6 15/16″
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