Rockford Fosgate Power T115D4 (2004)

15″ subwoofer · dual 4 Ω · 600 W RMS

Fs 27 HzQts 0.51Vas 3.15 ft³Xmax 0.55″

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 volume2.19 ft³ (62 L)
Qtc0.80
Fc42 Hz
F3 (−3 dB, no cabin gain)40 Hz
Example box (outside)16 15/16″ × 16 15/16″ × 18 7/16″
Open sealed box in designer

Ported

Net volume4.73 ft³ (134 L)
Tuning (Fb)27 Hz
Portslot 2 3/8 × 16 5/16″, 24 11/16″ long
Port velocity at 600 W65 ft/s
F3 (−3 dB, no cabin gain)24 Hz
Example box (outside)31 1/2″ × 17 11/16″ × 21 1/8″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs27 Hz
Qts0.51
Qes0.56
Qms6.05
Vas3.15 ft³
Re (one coil)3.1 Ω
Sd122.5 in²
Xmax0.55″
Vd67.5 in³ calc.
Mms345 g calc.
BL18 T·m calc.
EBP48 — suits sealed calc.
Sensitivity, 1 W / 1 m87 dB calc.

General

Size15″
Voice coilsdual 4 Ω
RMS power600 W

Mounting dimensions

Ø15 3/4″cutout Ø13 13/16″mounting depth 8 1/2″magnet Ø≈ 9″
Cutout diameter13 13/16″
Mounting depth8 1/2″
Overall diameter15 3/4″

“≈” 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 Rockford Fosgate 15″ models