Ground Zero GZNW 38SPL-D1 (2x1 Ohm)

15″ subwoofer · dual 1 Ω · 3,500 W RMS

Fs 36 HzQts 0.52Vas 1.91 ft³Xmax 3.15″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 3,500 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 volume1.52 ft³ (43 L)
Qtc0.78
Fc54 Hz
F3 (−3 dB, no cabin gain)52 Hz
Example box (outside)17 5/16″ × 17 5/16″ × 13″
Open sealed box in designer

Ported

Net volume4.38 ft³ (124 L)
Tuning (Fb)30 Hz
Portslot 5 7/8 × 16 11/16″, 58 11/16″ long
Port velocity at 3,500 W67 ft/s
F3 (−3 dB, no cabin gain)27 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 29 1/2″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs36 Hz
Qts0.52
Qes0.569
Qms6
Vas1.91 ft³
Re (one coil)≈ 0.85 Ω
Sd≈ 124 in²
Xmax3.15″
EBP63 — sealed or ported calc.
Sensitivity, 1 W / 1 m88.5 dB calc.

General

Size15″
Voice coilsdual 1 Ω
RMS power3,500 W

Mounting dimensions

Ø≈ 15 1/4″cutout Ø14 1/8″mounting depth 10 9/16″magnet Ø10 1/4″
Cutout diameter14 1/8″
Mounting depth10 9/16″
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