Ground Zero GZHW 20SPL (2x2 Ohm)

8″ subwoofer · dual 1 Ω · 700 W RMS

Fs 38.3 HzQts 0.38Vas 0.17 ft³Xmax 0.79″

Recommended box

For a sedan, one sub, 700 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 volume0.30 ft³ (8.5 L)
Qtc0.48
Fc48 Hz
F3 (−3 dB, no cabin gain)81 Hz
Example box (outside)10 5/8″ × 10 5/8″ × 8 1/4″
Open sealed box in designer

Ported

Net volume0.57 ft³ (16 L)
Tuning (Fb)26 Hz
Portslot 1 15/16 × 14 5/16″, 193 1/16″ long
Port velocity at 700 W37 ft/s
F3 (−3 dB, no cabin gain)61 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 17 11/16″

The volume and tuning are the recommendation, but the port doesn’t fit this example box. Size the box and port in the designer.

Open ported box in designer
2030405060801001502005460667278HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs38.3 Hz
Qts0.38
Qes0.407
Qms6.04
Vas0.17 ft³
Re (one coil)1 Ω
Sd30.3 in²
Xmax0.79″
Vd23.9 in³ calc.
Mms197 g calc.
BL10.8 T·m calc.
EBP94 — sealed or ported calc.
Sensitivity, 1 W / 1 m80.2 dB calc.

General

Size8″
Voice coilsdual 1 Ω
RMS power700 W

Mounting dimensions

Ø≈ 8 9/16″cutout Ø7 3/8″mounting depth 5 11/16″magnet Ø6 5/8″
Cutout diameter7 3/8″
Mounting depth5 11/16″
Magnet diameter6 5/8″

Cone area (Sd) calculated from Fs, Vas and Mms: 30.4 in².

“≈” 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 8″ models