Alpine SWR-1243D (Type-R)

12″ subwoofer · dual 4 Ω · 600 W RMS

Fs 31 HzQts 0.53Vas 1.34 ft³Xmax 0.79″

Recommended box

For a sedan, one sub, 600 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 volume1.06 ft³ (30 L)
Qtc0.80
Fc47 Hz
F3 (−3 dB, no cabin gain)44 Hz
Example box (outside)14 3/16″ × 14 3/16″ × 13 13/16″
Open sealed box in designer

Ported

Net volume2.90 ft³ (82 L)
Tuning (Fb)27 Hz
Portslot 2 3/8 × 14 5/16″, 38 1/16″ long
Port velocity at 600 W61 ft/s
F3 (−3 dB, no cabin gain)24 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 17 3/16″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs31 Hz
Qts0.53
Qes0.57
Qms7.9
Vas1.34 ft³
Re (one coil)3.7 Ω
Sd74.4 in²
Xmax0.79″
Vd58.6 in³ calc.
Mms226 g calc.
BL16.9 T·m calc.
EBP54 — sealed or ported calc.
Sensitivity, 1 W / 1 m85 dB calc.

General

Size12″
Voice coilsdual 4 Ω
RMS power600 W

Mounting dimensions

Ø12 5/8″cutout Ø10 13/16″mounting depth 6 3/8″magnet Ø≈ 7 1/16″
Cutout diameter10 13/16″
Mounting depth6 3/8″
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