Alpine R2-W8D4

8″ subwoofer · dual 4 Ω · 350 W RMS

Fs 43 HzQts 0.54Vas 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 volume0.32 ft³ (9 L)
Qtc0.79
Fc63 Hz
F3 (−3 dB, no cabin gain)60 Hz
Example box (outside)10 5/8″ × 10 5/8″ × 8 5/8″
Open sealed box in designer

Ported

Net volume0.92 ft³ (26 L)
Tuning (Fb)35 Hz
Port2 round ports Ø2 1/2″, 21 7/8″ long
Port velocity at 350 W105 ft/s
F3 (−3 dB, no cabin gain)31 Hz
Example box (outside)25 5/16″ × 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

Fs43 Hz
Qts0.54
Qes0.58
Qms7.08
Vas0.37 ft³
Re (one coil)3.6 Ω
Sd31.2 in²
Xmax0.47″
Vd14.7 in³ calc.
Mms75 g calc.
BL11.2 T·m calc.
EBP74 — sealed or ported calc.
Sensitivity, 1 W / 1 m83.6 dB calc.

General

Size8″
Voice coilsdual 4 Ω
RMS power350 W

Mounting dimensions

Ø8 1/2″cutout ≈ Ø7 5/8″mounting depth 4 9/16″magnet Ø≈ 4 15/16″
Cutout diameter≈ 7 5/8″
Mounting depth4 9/16″
Overall diameter8 1/2″

“≈” 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