ESX SX1240 (4 Ohm)

12″ subwoofer · 4 Ω · 500 W RMS

Fs 28 HzQts 0.35Vas 2.86 ft³Xmax 0.59″

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 volume0.71 ft³ (20 L)
Qtc0.78
Fc63 Hz
F3 (−3 dB, no cabin gain)62 Hz
Example box (outside)14 3/16″ × 14 3/16″ × 10 1/16″
Open sealed box in designer

Ported

Net volume2.05 ft³ (58 L)
Tuning (Fb)34 Hz
Portslot 1 3/4 × 14 5/16″, 24 1/2″ long
Port velocity at 500 W65 ft/s
F3 (−3 dB, no cabin gain)33 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 11 15/16″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs28 Hz
Qts0.35
Qes0.37
Qms5.3
Vas2.86 ft³
Re3.2 Ω
Sd78.3 in²
Xmax0.59″
Vd46.2 in³ calc.
Mms144 g calc.
BL14.8 T·m calc.
EBP76 — sealed or ported calc.
Sensitivity, 1 W / 1 m88.8 dB calc.

General

Size12″
Voice coils4 Ω
RMS power500 W

Mounting dimensions

Ø12 3/8″cutout Ø11 1/8″mounting depth 5 1/2″magnet Ø≈ 7 3/16″
Cutout diameter11 1/8″
Mounting depth5 1/2″
Overall diameter12 3/8″

“≈” 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 ESX 12″ models