Sundown Audio Uv1-18 D4

18″ subwoofer · dual 4 Ω · 1,500 W RMS

Fs 31.4 HzQts 0.38Vas 4.78 ft³

Recommended box

For a sedan, one sub, 1,500 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 volume1.80 ft³ (51 L)
Qtc0.72
Fc60 Hz
F3 (−3 dB, no cabin gain)63 Hz
Example box (outside)19 11/16″ × 19 11/16″ × 12 3/16″
Open sealed box in designer

Ported

Net volume4.31 ft³ (122 L)
Tuning (Fb)35 Hz
Portslot 3 3/8 × 19 1/16″, 25 11/16″ long
Port velocity at 1,500 W65 ft/s
F3 (−3 dB, no cabin gain)34 Hz
Example box (outside)31 1/2″ × 20 1/2″ × 18 9/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs31.4 Hz
Qts0.38
Qes0.42
Qms3.55
Vas4.78 ft³
Re (one coil)3.05 Ω
Sd198.6 in²
Xmax≈ 0.39″
Mms441 g calc.
BL25.1 T·m calc.
EBP75 — sealed or ported calc.
Sensitivity, 1 W / 1 m92 dB calc.

General

Size18″
Voice coilsdual 4 Ω
RMS power1,500 W

Mounting dimensions

Ø≈ 17 11/16″cutout ≈ Ø16 9/16″mounting depth ≈ 8 1/4″magnet Ø≈ 10 3/4″
Cutout diameter≈ 16 9/16″
Mounting depth≈ 8 1/4″

Cone area (Sd) calculated from Fs, Vas and Mms: 198.6 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