Sundown Audio Xv3-18 D2

18″ subwoofer · dual 2 Ω · 2,000 W RMS

Fs 28.2 HzQts 0.54Vas 3.88 ft³Xmax 1.18″

Recommended box

For a sedan, one sub, 2,000 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 volume3.28 ft³ (93 L)
Qtc0.80
Fc42 Hz
F3 (−3 dB, no cabin gain)39 Hz
Example box (outside)19 11/16″ × 19 11/16″ × 19 7/8″
Open sealed box in designer

Ported

Net volume6.64 ft³ (188 L)
Tuning (Fb)27 Hz
Portslot 4 1/8 × 19 1/16″, 36 3/16″ long
Port velocity at 2,000 W65 ft/s
F3 (−3 dB, no cabin gain)24 Hz
Example box (outside)31 1/2″ × 20 1/2″ × 27 7/8″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs28.2 Hz
Qts0.54
Qes0.657
Qms3.09
Vas3.88 ft³
Re (one coil)1.6 Ω
Sd171.8 in²
Xmax1.18″
Vd203 in³ calc.
Mms504 g calc.
BL14.7 T·m calc.
EBP43 — suits sealed calc.
Sensitivity, 1 W / 1 m87.8 dB calc.

General

Size18″
Voice coilsdual 2 Ω
RMS power2,000 W

Mounting dimensions

Ø18 7/16″cutout Ø16 11/16″mounting depth 10 1/4″magnet Ø8 11/16″
Cutout diameter16 11/16″
Mounting depth10 1/4″
Overall diameter18 7/16″
Magnet diameter8 11/16″

The spec sheet's Sd of 254.5 in² is the area of a 18″ circle, not the cone's radiating area — not used.

Cone area (Sd) calculated from Fs, Vas and Mms: 171.8 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 Sundown Audio 18″ models