Sundown Audio SML-8 D2

8″ subwoofer · dual 2 Ω · 400 W RMS

Fs 43.2 HzQts 0.47Vas 0.31 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)
Qtc0.66
Fc61 Hz
F3 (−3 dB, no cabin gain)68 Hz
Example box (outside)10 5/8″ × 10 5/8″ × 8 5/8″
Open sealed box in designer

Ported

Net volume0.64 ft³ (18 L)
Tuning (Fb)36 Hz
Portround port Ø2 1/2″, 14 5/16″ long
Port velocity at 400 W184 ft/s
F3 (−3 dB, no cabin gain)33 Hz
Example box (outside)19 3/4″ × 15 3/4″ × 6 5/16″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs43.2 Hz
Qts0.47
Qes0.514
Qms5.34
Vas0.31 ft³
Re (one coil)1.93 Ω
Sd33.3 in²
Xmax0.55″
Vd18.3 in³ calc.
Mms101 g calc.
BL10.1 T·m calc.
EBP84 — sealed or ported calc.
Sensitivity, 1 W / 1 m83.4 dB calc.

General

Size8″
Voice coilsdual 2 Ω
RMS power400 W

Mounting dimensions

Ø8 1/2″cutout Ø7 5/8″mounting depth 3 7/8″magnet Ø6 1/8″
Cutout diameter7 5/8″
Mounting depth3 7/8″
Overall diameter8 1/2″
Magnet diameter6 1/8″

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: 33.3 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