Rockville W8T4S4

8″ subwoofer · 4 Ω · 250 W RMS

Fs 82.4 HzQts 0.88Vas 0.21 ft³

Recommended box

For a sedan, one sub, 250 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 volume0.42 ft³ (12 L)
Qtc1.08
Fc101 Hz
F3 (−3 dB, no cabin gain)79 Hz
Example box (outside)10 1/4″ × 10 1/4″ × 11 5/8″
Open sealed box in designer

Ported

Net volume1.27 ft³ (36 L)
Tuning (Fb)50 Hz
Portslot 1 9/16 × 14 5/16″, 15 1/16″ long
Port velocity at 250 W58 ft/s
F3 (−3 dB, no cabin gain)43 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 7 11/16″
Open ported box in designer
203040506080100150200667278849096HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs82.4 Hz
Qts0.88
Qes0.993
Qms7.97
Vas0.21 ft³
Re3.6 Ω
Sd33.2 in²
Xmax≈ 0.39″
Mms40 g calc.
BL8.7 T·m calc.
EBP83 — sealed or ported calc.
Sensitivity, 1 W / 1 m87.3 dB calc.

General

Size8″
Voice coils4 Ω
RMS power250 W

Mounting dimensions

Ø8 1/2″cutout Ø7″mounting depth 2 1/2″magnet Ø≈ 4 9/16″
Cutout diameter7″
Mounting depth2 1/2″
Overall diameter8 1/2″

Cone area (Sd) calculated from Fs, Vas and Mms: 33.2 in².

“≈” 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 Rockville 8″ models