Ground Zero GZNW 38XMAX-II (2x1 Ohm)

15″ subwoofer · dual 1 Ω · 4,000 W RMS

Fs 31 HzQts 0.51Vas 0.93 ft³Xmax 2.44″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 4,000 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 volume1.71 ft³ (48.5 L)
Qtc0.63
Fc38 Hz
F3 (−3 dB, no cabin gain)45 Hz
Example box (outside)17 5/16″ × 17 5/16″ × 14 5/16″
Open sealed box in designer

Ported

Net volume2.37 ft³ (67 L)
Tuning (Fb)25 Hz
Portround port Ø3″, 10 1/2″ long
Port velocity at 4,000 W684 ft/s
F3 (−3 dB, no cabin gain)22 Hz
Example box (outside)22 5/16″ × 18 1/8″ × 14 3/8″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs31 Hz
Qts0.51
Qes0.557
Qms6
Vas0.93 ft³
Re (one coil)≈ 0.85 Ω
Sd≈ 124 in²
Xmax2.44″
EBP56 — sealed or ported calc.
Sensitivity, 1 W / 1 m83.5 dB calc.

General

Size15″
Voice coilsdual 1 Ω
RMS power4,000 W

Mounting dimensions

Ø≈ 15 3/8″cutout Ø14 3/16″mounting depth 11 13/16″magnet Ø10 1/4″
Cutout diameter14 3/16″
Mounting depth11 13/16″
Magnet diameter10 1/4″

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 15″ models