Sundown Audio Xv2-6.5 S4

6.5″ subwoofer · 4 Ω · 400 W RMS

Fs 55.8 HzQts 0.58Vas 0.06 ft³Xmax 0.63″

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 volume0.18 ft³ (5 L)
Qtc0.67
Fc64 Hz
F3 (−3 dB, no cabin gain)70 Hz
Example box (outside)8 11/16″ × 8 11/16″ × 7 13/16″
Open sealed box in designer

Ported

Net volume0.35 ft³ (10 L)
Tuning (Fb)34 Hz
Portslot 1 15/16 × 14 5/16″, 180 5/16″ long
Port velocity at 400 W26 ft/s
F3 (−3 dB, no cabin gain)30 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 15 13/16″

The volume and tuning are the recommendation, but the port doesn’t fit this example box. Size the box and port in the designer.

Open ported box in designer
2030405060801001502005460667278HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs55.8 Hz
Qts0.58
Qes0.619
Qms9.26
Vas0.06 ft³
Re2.9 Ω
Sd17 in²
Xmax0.63″
Vd10.7 in³ calc.
Mms83 g calc.
BL11.7 T·m calc.
EBP90 — sealed or ported calc.
Sensitivity, 1 W / 1 m78.7 dB calc.

General

Size6.5″
Voice coils4 Ω
RMS power400 W

Mounting dimensions

Ø6 3/4″cutout Ø5 1/2″mounting depth 4″magnet Ø≈ 3 9/16″
Cutout diameter5 1/2″
Mounting depth4″
Overall diameter6 3/4″

“≈” 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 Sundown Audio 6.5″ models