Fi Audio IB315 v2 S4

15″ subwoofer · 4 Ω · 600 W RMS

Fs 26.1 HzQts 0.76Vas 4.04 ft³Xmax 1.34″

Recommended box

For a sedan, one sub, 600 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 volume2.86 ft³ (81 L)
Qtc1.18
Fc41 Hz
F3 (−3 dB, no cabin gain)31 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 11 7/8″
Open sealed box in designer

Ported

Net volume4.87 ft³ (138 L)
Tuning (Fb)31 Hz
Portslot 2 3/8 × 16 11/16″, 17 5/16″ long
Port velocity at 600 W61 ft/s
F3 (−3 dB, no cabin gain)26 Hz
Example box (outside)31 1/2″ × 18 1/8″ × 20 1/2″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs26.1 Hz
Qts0.76
Qes0.83
Qms8.73
Vas4.04 ft³
Re3.6 Ω
Sd125.6 in²
Xmax1.34″
Vd168.1 in³ calc.
Mms302 g calc.
BL14.7 T·m calc.
EBP31 — suits sealed calc.
Sensitivity, 1 W / 1 m85.9 dB calc.

General

Size15″
Voice coils4 Ω
RMS power600 W

Mounting dimensions

Ø15 5/8″cutout Ø14 1/8″mounting depth 8″magnet Ø≈ 9 3/16″
Cutout diameter14 1/8″
Mounting depth8″
Overall diameter15 5/8″

“≈” 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