Rockford Fosgate Punch HX2 RFD2208

8″ subwoofer · dual 4 Ω · 400 W RMS

Fs 40 HzQts 0.49Vas 0.32 ft³Xmax 0.55″

Recommended box

For a sedan, one sub, 400 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 volume0.32 ft³ (9 L)
Qtc0.70
Fc57 Hz
F3 (−3 dB, no cabin gain)60 Hz
Example box (outside)10 1/4″ × 10 1/4″ × 9 1/4″
Open sealed box in designer

Ported

Net volume0.64 ft³ (18 L)
Tuning (Fb)38 Hz
Portround port Ø2 1/2″, 12 11/16″ long
Port velocity at 400 W193 ft/s
F3 (−3 dB, no cabin gain)34 Hz
Example box (outside)16 1/16″ × 15 3/4″ × 7 5/16″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs40 Hz
Qts0.49
Qes0.53
Qms6.9
Vas0.32 ft³
Re (one coil)3.6 Ω
Sd33.9 in²
Xmax0.55″
Vd18.7 in³ calc.
Mms120 g calc.
BL14.3 T·m calc.
EBP75 — sealed or ported calc.
Sensitivity, 1 W / 1 m82.4 dB calc.

General

Size8″
Voice coilsdual 4 Ω
RMS power400 W

Mounting dimensions

Ø8 5/8″cutout Ø6 7/8″mounting depth 4 13/16″magnet Ø≈ 4 1/2″
Cutout diameter6 7/8″
Mounting depth4 13/16″
Overall diameter8 5/8″

Judging by its value, the published Re is for both coils in parallel — converted to per coil.

“≈” 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 8″ models