Sundown Audio Xv2-8 D2

8″ subwoofer · dual 2 Ω · 750 W RMS

46.8 HzFs, resonance
0.48Qts
0.15 ft³Vas
0.75″Xmax
750 WRMS
Sourceweb.archive.org · manufacturer data
Checked against sourceOctober 2026
Thiele/Small parameterscomplete
Mounting dimensions3 of 4 — missing: magnet diameter; the designer will use an estimate

Recommended box

For a sedan, one sub, 750 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

smaller, tighter
0.37 ft³ (10.5 L)
Net volume
Bass character (Qtc)Dry and tight · 0.57
Fc55 Hz
F3 (−3 dB, no cabin gain)73 Hz
Example box (outside)10 5/8″ × 10 5/8″ × 9 11/16″
Open sealed box in designer

Ported

deeper, louder
0.49 ft³ (14 L)
Net volume
Tuning (Fb)41 Hz
Portslot 1 15/16 × 14 5/16″, 86 3/8″ long
Port velocity at 750 W44 ft/s
F3 (−3 dB, no cabin gain)36 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 10 1/16″

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

Deeper: 0.60 ft³ (17 L) tuned to 31 Hz, 31 1/2″ × 15 3/4″ × 13 1/4″ outside — a bigger box with flatter deep bass. Open in the calculator

Where to buy Amazon
2030405060801001502006066727884HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Size8″
Voice coilsdual 2 Ω
RMS power750 W
Fs46.8 Hz
Qts0.48
Qes0.544
Qms4.43
Vas0.15 ft³
Re (one coil)2 Ω
Sd31.2 in²
Xmax0.75″
Vd23.3 in³ calc.
Mms159 g calc.
BL13.1 T·m calc.
EBP86 — sealed or ported calc.
Sensitivity, 1 W / 1 m81 dB calc.

Mounting dimensions

Ø8 11/16″cutout Ø7 3/8″mounting depth 7″magnet Ø≈ 4 13/16″
Cutout diameter7 3/8″
Mounting depth7″
Overall diameter8 11/16″

Cone area (Sd) calculated from Fs, Vas and Mms: 31.2 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

Similar 8″ subwoofers from other brands

Close in Fs, Qts and Vas — a box of similar volume will suit them.

FAQ

What box does the Sundown Audio Xv2-8 D2 need?

Recommended net volume: 0.37 ft³ sealed, 0.49 ft³ ported tuned to 41 Hz — for one sub in a sedan at 750 W. Fit the box to your space and amp in the free calculator, with plans and a cut sheet.

What are the Sundown Audio Xv2-8 D2 Thiele/Small specs?

Fs 46.8 Hz, Qts 0.48, Vas 0.15 ft³, Xmax 0.75″, Sd 31.2 in².

What is the Sundown Audio Xv2-8 D2 mounting depth?

Mounting depth is 7″, cutout diameter 7 3/8″. The inside depth of the box must exceed the mounting depth by at least 1″.

How much power does the Sundown Audio Xv2-8 D2 handle and how do I wire it?

RMS power rating: 750 W. Dual 2 Ω voice coils: series gives 4 Ω, parallel gives 1 Ω at the amp. Wiring for several subs and amp power — in the wiring calculator.