Fi Audio BL18v3 D1

18″ subwoofer · dual 1 Ω · 1,750 W RMS

Fs 33.6 HzQts 0.40Vas 4.80 ft³Xmax 0.79″

Recommended box

For a sedan, one sub, 1,750 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 volume1.89 ft³ (53.5 L)
Qtc0.75
Fc63 Hz
F3 (−3 dB, no cabin gain)63 Hz
Example box (outside)20 1/16″ × 20 1/16″ × 12 3/16″
Open sealed box in designer

Ported

Net volume5.19 ft³ (147 L)
Tuning (Fb)35 Hz
Portslot 4 1/8 × 19 7/16″, 26 3/8″ long
Port velocity at 1,750 W64 ft/s
F3 (−3 dB, no cabin gain)33 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 21 5/8″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs33.6 Hz
Qts0.40
Qes0.42
Qms8.21
Vas4.80 ft³
Re (one coil)0.7 Ω
Sd187.6 in²
Xmax0.79″
Vd147.7 in³ calc.
Mms342 g calc.
BL11 T·m calc.
EBP80 — sealed or ported calc.
Sensitivity, 1 W / 1 m92.9 dB calc.

General

Size18″
Voice coilsdual 1 Ω
RMS power1,750 W

Mounting dimensions

Ø18 1/2″cutout Ø16 3/4″mounting depth 9 3/4″magnet Ø≈ 10 7/8″
Cutout diameter16 3/4″
Mounting depth9 3/4″
Overall diameter18 1/2″

“≈” 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 Fi Audio 18″ models