Skar Audio SDR-8 D4

8″ subwoofer · dual 4 Ω · 350 W RMS

Fs 39 HzQts 0.60Vas 0.25 ft³Xmax 0.35″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 350 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)
Qtc0.80
Fc52 Hz
F3 (−3 dB, no cabin gain)49 Hz
Example box (outside)10 1/4″ × 10 1/4″ × 9 1/4″
Open sealed box in designer

Ported

Net volume0.85 ft³ (24 L)
Tuning (Fb)29 Hz
Portround port Ø2 1/2″, 16 7/8″ long
Port velocity at 350 W186 ft/s
F3 (−3 dB, no cabin gain)25 Hz
Example box (outside)21 15/16″ × 15 3/4″ × 7 1/16″
Open ported box in designer
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs39 Hz
Qts0.60
Qes0.68
Qms5.1
Vas0.25 ft³
Re (one coil)≈ 3.4 Ω
Sd31.2 in²
Xmax0.35″
Vd10.8 in³ calc.
Mms137 g calc.
BL12.9 T·m calc.
EBP57 — sealed or ported calc.
Sensitivity, 1 W / 1 m79.9 dB calc.

General

Size8″
Voice coilsdual 4 Ω
RMS power350 W

Mounting dimensions

Ø8 7/16″cutout Ø7 3/16″mounting depth 4 11/16″magnet Ø5 1/4″
Cutout diameter7 3/16″
Mounting depth4 11/16″
Overall diameter8 7/16″
Magnet diameter5 1/4″

“≈” 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 Skar Audio 8″ models