Alpine SWR-1222D (Type-R)

12″ subwoofer · dual 2 Ω · 500 W RMS

Fs 28 HzQts 0.42Vas 1.59 ft³Xmax 0.71″

Recommended box

For a sedan, one sub, 500 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 volume0.72 ft³ (20.5 L)
Qtc0.75
Fc50 Hz
F3 (−3 dB, no cabin gain)50 Hz
Example box (outside)14 3/16″ × 14 3/16″ × 10 1/4″
Open sealed box in designer

Ported

Net volume1.94 ft³ (55 L)
Tuning (Fb)29 Hz
Portslot 1 3/4 × 14 5/16″, 37 3/8″ long
Port velocity at 500 W62 ft/s
F3 (−3 dB, no cabin gain)27 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 12 5/8″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs28 Hz
Qts0.42
Qes0.44
Qms8.25
Vas1.59 ft³
Re (one coil)1.85 Ω
Sd74.4 in²
Xmax0.71″
Vd53 in³ calc.
Mms234 g calc.
BL13.2 T·m calc.
EBP64 — sealed or ported calc.
Sensitivity, 1 W / 1 m85.5 dB calc.

General

Size12″
Voice coilsdual 2 Ω
RMS power500 W

Mounting dimensions

Ø12 5/8″cutout Ø10 13/16″mounting depth 7 11/16″magnet Ø≈ 7 1/16″
Cutout diameter10 13/16″
Mounting depth7 11/16″
Overall diameter12 5/8″

“≈” 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 Alpine 12″ models