Ground Zero GZIW 300 (4 Ohm)

12″ subwoofer · 4 Ω · 350 W RMS

Fs 30 HzQts 0.58Vas 2.45 ft³Xmax 1.10″

Recommended box

For a sedan, one sub, 350 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 volume1.73 ft³ (49 L)
Qtc0.90
Fc47 Hz
F3 (−3 dB, no cabin gain)41 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 8 3/4″
Open sealed box in designer

Ported

Net volume2.93 ft³ (83 L)
Tuning (Fb)33 Hz
Portslot 1 3/4 × 14 5/16″, 17 1/8″ long
Port velocity at 350 W61 ft/s
F3 (−3 dB, no cabin gain)29 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 14 7/8″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs30 Hz
Qts0.58
Qes0.642
Qms6
Vas2.45 ft³
Re≈ 3.4 Ω
Sd≈ 76 in²
Xmax1.10″
EBP47 — suits sealed calc.
Sensitivity, 1 W / 1 m86.7 dB calc.

General

Size12″
Voice coils4 Ω
RMS power350 W

Mounting dimensions

Ø≈ 12 1/2″cutout Ø11 5/16″mounting depth 5 7/8″magnet Ø≈ 7 3/8″
Cutout diameter11 5/16″
Mounting depth5 7/8″

Only Qts is published — Qms assumed to be 6 and Qes calculated (barely affects box design).

“≈” 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 Ground Zero 12″ models