Rockford Fosgate Prime R2SD4-12 (Shallow)

12″ subwoofer · dual 4 Ω · 250 W RMS

Fs 30.3 HzQts 0.65Vas 2.31 ft³Xmax 0.39″

Recommended box

For a sedan, one sub, 250 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 volume1.87 ft³ (53 L)
Qtc0.98
Fc45 Hz
F3 (−3 dB, no cabin gain)38 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 9 3/8″
Open sealed box in designer

Ported

Net volume3.21 ft³ (91 L)
Tuning (Fb)32 Hz
Portslot 1 9/16 × 14 5/16″, 14 7/16″ long
Port velocity at 250 W59 ft/s
F3 (−3 dB, no cabin gain)28 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 15 3/4″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs30.3 Hz
Qts0.65
Qes0.72
Qms7
Vas2.31 ft³
Re (one coil)3.4 Ω
Sd82.9 in²
Xmax0.39″
Vd32.6 in³ calc.
Mms171 g calc.
BL12.4 T·m calc.
EBP42 — suits sealed calc.
Sensitivity, 1 W / 1 m86 dB calc.

General

Size12″
Voice coilsdual 4 Ω
RMS power250 W

Mounting dimensions

Ø≈ 12 3/8″cutout Ø11 1/4″mounting depth 3 9/16″magnet Ø≈ 7 5/16″
Cutout diameter11 1/4″
Mounting depth3 9/16″

“≈” 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 Rockford Fosgate 12″ models