Earthquake DBXI-15D

15″ subwoofer · dual 4 Ω · 750 W RMS

Fs 20 HzQts 0.96Vas 3.22 ft³
The published specs don’t add up:

Recommended box

For a sedan, one sub, 750 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 volume2.83 ft³ (80 L)
Qtc1.40
Fc29 Hz
F3 (−3 dB, no cabin gain)21 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 11 3/4″
Open sealed box in designer

Ported

Net volume4.80 ft³ (136 L)
Tuning (Fb)25 Hz
Portslot 2 3/8 × 16 11/16″, 29 15/16″ long
Port velocity at 750 W61 ft/s
F3 (−3 dB, no cabin gain)20 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 21 7/16″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs20 Hz
Qts0.96
Qes1.14
Qms5.99
Vas3.22 ft³
Re (one coil)4 Ω
Sd≈ 124 in²
Xmax≈ 0.39″
EBP18 — suits sealed calc.
Sensitivity, 1 W / 1 m80.1 dB calc.

General

Size15″
Voice coilsdual 4 Ω
RMS power750 W

Mounting dimensions

Ø15 9/16″cutout ≈ Ø14″mounting depth 7 15/16″magnet Ø≈ 9 1/8″
Cutout diameter≈ 14″
Mounting depth7 15/16″
Overall diameter15 9/16″

“≈” 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 Earthquake 15″ models