Fi Audio FiDay 15

15″ subwoofer · 2 Ω · 350 W RMS

Fs 29.8 HzQts 0.38Vas 5.92 ft³Xmax 0.75″

Recommended box

For a sedan, one sub, 350 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 volume1.73 ft³ (49 L)
Qtc0.80
Fc63 Hz
F3 (−3 dB, no cabin gain)60 Hz
Example box (outside)17 5/16″ × 17 5/16″ × 14 7/16″
Open sealed box in designer

Ported

Net volume4.87 ft³ (138 L)
Tuning (Fb)34 Hz
Portslot 1 15/16 × 16 11/16″, 10 7/8″ long
Port velocity at 350 W64 ft/s
F3 (−3 dB, no cabin gain)33 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 19 11/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs29.8 Hz
Qts0.38
Qes0.41
Qms5.42
Vas5.92 ft³
Re1.9 Ω
Sd125.6 in²
Xmax0.75″
Vd93.9 in³ calc.
Mms158 g calc.
BL11.7 T·m calc.
EBP73 — sealed or ported calc.
Sensitivity, 1 W / 1 m92.3 dB calc.

General

Size15″
Voice coils2 Ω
RMS power350 W

Mounting dimensions

Ø≈ 15 3/16″cutout ≈ Ø14″mounting depth ≈ 7 1/16″magnet Ø≈ 9 1/16″
Cutout diameter≈ 14″
Mounting depth≈ 7 1/16″

“≈” 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 15″ models