Pride UFO.4 18 D0.7

18″ subwoofer · dual 0.7 Ω · 5,000 W RMS

Fs 27 HzQts 0.17Vas 3.04 ft³Xmax 1.57″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 5,000 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 volume2.38 ft³ (67.5 L)
Qtc0.26
Fc41 Hz
F3 (−3 dB, no cabin gain)150 Hz
Example box (outside)20 1/16″ × 20 1/16″ × 14 5/8″
Open sealed box in designer

Ported

Net volume3.57 ft³ (101 L)
Tuning (Fb)25 Hz
Portslot 2 9/16 × 19 7/16″, 53 7/8″ long
Port velocity at 5,000 W141 ft/s
F3 (−3 dB, no cabin gain)142 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 18 7/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs27 Hz
Qts0.17
Qes0.175
Qms6
Vas3.04 ft³
Re (one coil)2.8 Ω
Sd186 in²
Xmax1.57″
Vd292.9 in³ calc.
Mms824 g calc.
BL47.3 T·m calc.
EBP154 — suits ported calc.
Sensitivity, 1 W / 1 m91.9 dB calc.

General

Size18″
Voice coilsdual 0.7 Ω
RMS power5,000 W

Mounting dimensions

Ø18 1/4″cutout Ø16 15/16″mounting depth 12 3/16″magnet Ø≈ 11″
Cutout diameter16 15/16″
Mounting depth12 3/16″
Overall diameter18 1/4″

Only Qts is published — Qms assumed to be 6 and Qes calculated (barely affects box design).

“≈” 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 Pride 18″ models