Earthquake Magma-15X

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

Fs 20.2 HzQts 0.30Vas 7.42 ft³Xmax 0.75″

Recommended box

For a sedan, one sub, 1,000 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 volume1.27 ft³ (36 L)
Qtc0.79
Fc53 Hz
F3 (−3 dB, no cabin gain)51 Hz
Example box (outside)17 5/16″ × 17 5/16″ × 11 5/16″
Open sealed box in designer

Ported

Net volume3.57 ft³ (101 L)
Tuning (Fb)28 Hz
Portslot 2 9/16 × 16 11/16″, 35 7/16″ long
Port velocity at 1,000 W63 ft/s
F3 (−3 dB, no cabin gain)28 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 18″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs20.2 Hz
Qts0.30
Qes0.322
Qms4.79
Vas7.42 ft³
Re (one coil)4 Ω
Sd138 in²
Xmax0.75″
Vd103.7 in³ calc.
Mms331 g calc.
BL22.9 T·m calc.
EBP63 — sealed or ported calc.
Sensitivity, 1 W / 1 m89.3 dB calc.

General

Size15″
Voice coilsdual 4 Ω
RMS power1,000 W

Mounting dimensions

Ø≈ 15 1/4″cutout Ø14 1/16″mounting depth 8″magnet Ø≈ 9 1/8″
Cutout diameter14 1/16″
Mounting depth8″

Judging by its value, the published Re is for both coils in series — converted to per coil.

“≈” 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