Fi Audio NEO 4.11 18 D2

18″ subwoofer · dual 2 Ω · 3,500 W RMS

Fs 33.4 HzQts 0.34Vas 3.36 ft³Xmax 1.34″

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 volume2.38 ft³ (67.5 L)
Qtc0.52
Fc52 Hz
F3 (−3 dB, no cabin gain)78 Hz
Example box (outside)20 1/16″ × 20 1/16″ × 14 5/8″
Open sealed box in designer

Ported

Net volume3.60 ft³ (102 L)
Tuning (Fb)34 Hz
Portslot 4 15/16 × 19 7/16″, 53 3/8″ long
Port velocity at 3,500 W65 ft/s
F3 (−3 dB, no cabin gain)33 Hz
Example box (outside)31 1/2″ × 20 7/8″ × 22 1/2″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs33.4 Hz
Qts0.34
Qes0.35
Qms8.44
Vas3.36 ft³
Re (one coil)1.4 Ω
Sd187.6 in²
Xmax1.34″
Vd251.1 in³ calc.
Mms495 g calc.
BL20.4 T·m calc.
EBP95 — sealed or ported calc.
Sensitivity, 1 W / 1 m92.1 dB calc.

General

Size18″
Voice coilsdual 2 Ω
RMS power3,500 W

Mounting dimensions

Ø18 1/2″cutout Ø16 3/4″mounting depth 12 1/4″magnet Ø≈ 10 7/8″
Cutout diameter16 3/4″
Mounting depth12 1/4″
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