Sundown Audio Xv3-18 D1

18″ subwoofer · dual 1 Ω · 2,000 W RMS

Fs 26.7 HzQts 0.44Vas 4.60 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 volume2.01 ft³ (57 L)
Qtc0.80
Fc48 Hz
F3 (−3 dB, no cabin gain)46 Hz
Example box (outside)19 11/16″ × 19 11/16″ × 13 5/16″
Open sealed box in designer

Ported

Net volume6.64 ft³ (188 L)
Tuning (Fb)26 Hz
Portslot 4 5/16 × 19 1/16″, 41 5/8″ long
Port velocity at 2,000 W63 ft/s
F3 (−3 dB, no cabin gain)24 Hz
Example box (outside)31 1/2″ × 20 1/2″ × 29″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs26.7 Hz
Qts0.44
Qes0.526
Qms2.79
Vas4.60 ft³
Re (one coil)0.7 Ω
Sd171.4 in²
Xmax1.18″
Vd202.4 in³ calc.
Mms474 g calc.
BL10.3 T·m calc.
EBP51 — sealed or ported calc.
Sensitivity, 1 W / 1 m88.7 dB calc.

General

Size18″
Voice coilsdual 1 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: 171.4 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 Sundown Audio 18″ models