Memphis Car Audio PRX124 (Power Reference 12" SVC 4ohm)

12″ subwoofer · 4 Ω · 300 W RMS

Fs 36 HzQts 0.61Vas 1.50 ft³Xmax 0.51″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 300 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 volume1.70 ft³ (48 L)
Qtc0.84
Fc49 Hz
F3 (−3 dB, no cabin gain)45 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 8 5/8″
Open sealed box in designer

Ported

Net volume2.86 ft³ (81 L)
Tuning (Fb)33 Hz
Portslot 1 3/4 × 14 5/16″, 17 5/8″ long
Port velocity at 300 W60 ft/s
F3 (−3 dB, no cabin gain)29 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 14 5/8″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs36 Hz
Qts0.61
Qes0.7
Qms5.05
Vas1.50 ft³
Re≈ 3.4 Ω
Sd73.7 in²
Xmax0.51″
Vd37.7 in³ calc.
Mms147 g calc.
BL12.7 T·m calc.
EBP51 — sealed or ported calc.
Sensitivity, 1 W / 1 m86.5 dB calc.

General

Size12″
Voice coils4 Ω
RMS power300 W

Mounting dimensions

12 9/16″ × 12 9/16″cutout 11″mounting depth 5 9/16″magnet Ø6 7/16″
Cutout (square, side)11″
Mounting depth5 9/16″
Overall diameter12 9/16″
Magnet diameter6 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 Memphis Car Audio 12″ models