URAL Decibel 18 (1+1)

18″ subwoofer · dual 1 Ω · 3,500 W RMS

Fs 19.6 HzQts 0.44Vas 9.54 ft³Xmax 1.61″

Recommended box

For a sedan, one sub, 3,500 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 volume4.03 ft³ (114 L)
Qtc0.80
Fc36 Hz
F3 (−3 dB, no cabin gain)34 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 14 1/8″
Open sealed box in designer

Ported

Net volume7.06 ft³ (200 L)
Tuning (Fb)25 Hz
Portslot 5 1/8 × 19 7/16″, 52 1/16″ long
Port velocity at 3,500 W66 ft/s
F3 (−3 dB, no cabin gain)23 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 32 15/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs19.6 Hz
Qts0.44
Qes0.48
Qms4.66
Vas9.54 ft³
Re (one coil)≈ 0.85 Ω
Sd182.3 in²
Xmax1.61″
Vd294.3 in³ calc.
Mms478 g calc.
BL10.2 T·m calc.
EBP41 — suits sealed calc.
Sensitivity, 1 W / 1 m88.3 dB calc.

General

Size18″
Voice coilsdual 1 Ω
RMS power3,500 W

Mounting dimensions

Ø18 1/2″cutout Ø16 7/8″mounting depth 10 13/16″magnet Ø≈ 10 15/16″
Cutout diameter16 7/8″
Mounting depth10 13/16″
Overall diameter18 1/2″

Cone area (Sd) calculated from Fs, Vas and Mms: 182.3 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 URAL 18″ models