Sundown Audio SDv4-8 D4

8″ subwoofer · dual 4 Ω · 400 W RMS

Fs 36.3 HzQts 0.59Vas 0.45 ft³Xmax 0.57″

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 volume0.53 ft³ (15 L)
Qtc0.80
Fc49 Hz
F3 (−3 dB, no cabin gain)46 Hz
Example box (outside)9 13/16″ × 9 13/16″ × 15 3/16″
Open sealed box in designer

Ported

Net volume1.27 ft³ (36 L)
Tuning (Fb)29 Hz
Port2 round ports Ø2 1/2″, 23 1/16″ long
Port velocity at 400 W120 ft/s
F3 (−3 dB, no cabin gain)25 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 7 3/8″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs36.3 Hz
Qts0.59
Qes0.656
Qms5.73
Vas0.45 ft³
Re (one coil)3.22 Ω
Sd33.2 in²
Xmax0.57″
Vd19 in³ calc.
Mms98 g calc.
BL10.5 T·m calc.
EBP55 — sealed or ported calc.
Sensitivity, 1 W / 1 m81.7 dB calc.

General

Size8″
Voice coilsdual 4 Ω
RMS power400 W

Mounting dimensions

Ø8 1/8″cutout Ø6 3/4″mounting depth 4 1/2″magnet Ø4 1/2″
Cutout diameter6 3/4″
Mounting depth4 1/2″
Overall diameter8 1/8″
Magnet diameter4 1/2″

The spec sheet's Sd of 53.4 in² is the area of a 8″ circle, not the cone's radiating area — not used.

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 Sundown Audio 8″ models