Sundown Audio Uv2-18 D2

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

Fs 30.9 HzQts 0.51Vas 3.95 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 volume2.79 ft³ (79 L)
Qtc0.80
Fc48 Hz
F3 (−3 dB, no cabin gain)45 Hz
Example box (outside)20 1/16″ × 20 1/16″ × 16 11/16″
Open sealed box in designer

Ported

Net volume7.77 ft³ (220 L)
Tuning (Fb)28 Hz
Portslot 5 1/8 × 19 7/16″, 35 7/16″ long
Port velocity at 2,000 W64 ft/s
F3 (−3 dB, no cabin gain)25 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 31 13/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs30.9 Hz
Qts0.51
Qes0.566
Qms5.63
Vas3.95 ft³
Re (one coil)1.94 Ω
Sd201 in²
Xmax1.18″
Vd237.4 in³ calc.
Mms565 g calc.
BL19.4 T·m calc.
EBP55 — sealed or ported calc.
Sensitivity, 1 W / 1 m89.7 dB calc.

General

Size18″
Voice coilsdual 2 Ω
RMS power2,000 W

Mounting dimensions

Ø18 5/8″cutout Ø16 7/8″mounting depth 10″magnet Ø9 11/16″
Cutout diameter16 7/8″
Mounting depth10″
Overall diameter18 5/8″
Magnet diameter9 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: 201 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