JBL MS-12SD4

12″ subwoofer · dual 4 Ω · 450 W RMS

Fs 37 HzQts 0.85Vas 1.66 ft³Xmax 0.28″

Recommended box

For a sedan, one sub, 450 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 volume1.80 ft³ (51 L)
Qtc1.18
Fc51 Hz
F3 (−3 dB, no cabin gain)39 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 9 1/16″
Open sealed box in designer

Ported

Net volume3.04 ft³ (86 L)
Tuning (Fb)37 Hz
Portslot 2 3/16 × 14 5/16″, 15 3/8″ long
Port velocity at 450 W60 ft/s
F3 (−3 dB, no cabin gain)31 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 15 3/8″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs37 Hz
Qts0.85
Qes0.93
Qms10.45
Vas1.66 ft³
Re (one coil)3.85 Ω
Sd78.6 in²
Xmax0.28″
Vd21.7 in³ calc.
Mms143 g calc.
BL11.7 T·m calc.
EBP40 — suits sealed calc.
Sensitivity, 1 W / 1 m86.1 dB calc.

General

Size12″
Voice coilsdual 4 Ω
RMS power450 W

Mounting dimensions

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

“≈” 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 JBL 12″ models