Rockford Fosgate Punch Z RFZ3808

8″ subwoofer · 8 Ω · 150 W RMS

Fs 37 HzQts 0.51Vas 0.88 ft³Xmax 0.28″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 150 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 volume0.60 ft³ (17 L)
Qtc0.80
Fc58 Hz
F3 (−3 dB, no cabin gain)55 Hz
Example box (outside)10 1/4″ × 10 1/4″ × 15 9/16″
Open sealed box in designer

Ported

Net volume1.31 ft³ (37 L)
Tuning (Fb)36 Hz
Portslot 1 9/16 × 14 5/16″, 31 11/16″ long
Port velocity at 150 W33 ft/s
F3 (−3 dB, no cabin gain)33 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 9 1/8″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs37 Hz
Qts0.51
Qes0.58
Qms4.08
Vas0.88 ft³
Re10.2 Ω
Sd33.9 in²
Xmax0.28″
Vd9.4 in³ calc.
Mms50 g calc.
BL14.3 T·m calc.
EBP64 — sealed or ported calc.
Sensitivity, 1 W / 1 m85.4 dB calc.

General

Size8″
Voice coils8 Ω
RMS power150 W

Mounting dimensions

Ø≈ 8 1/4″cutout Ø7 1/16″mounting depth 3 7/8″magnet Ø≈ 4 9/16″
Cutout diameter7 1/16″
Mounting depth3 7/8″

“≈” 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 Rockford Fosgate 8″ models