Ground Zero GZPW 18SPL (2x1 Ohm)

18″ subwoofer · dual 1 Ω

Fs 34 HzQts 0.19Vas 3.07 ft³Xmax 0.69″
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 volume2.12 ft³ (60 L)
Qtc0.30
Fc53 Hz
F3 (−3 dB, no cabin gain)164 Hz
Example box (outside)19 11/16″ × 19 11/16″ × 13 7/8″
Open sealed box in designer

Ported

Net volume3.46 ft³ (98 L)
Tuning (Fb)31 Hz
Port2 round ports Ø3″, 9 1/8″ long
Port velocity at 300 W128 ft/s
F3 (−3 dB, no cabin gain)154 Hz
Example box (outside)29 1/4″ × 20 1/2″ × 14″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs34 Hz
Qts0.19
Qes0.21
Qms2.09
Vas3.07 ft³
Re (one coil)≈ 0.85 Ω
Sd≈ 180.6 in²
Xmax0.69″
EBP162 — suits ported calc.
Sensitivity, 1 W / 1 m94.1 dB calc.

General

Size18″
Voice coilsdual 1 Ω
RMS power—

Mounting dimensions

Ø≈ 17 11/16″cutout Ø16 9/16″mounting depth 11 7/16″magnet Ø11″
Cutout diameter16 9/16″
Mounting depth11 7/16″
Magnet diameter11″

“≈” 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 18″ models