Sundown Audio Xv3-15 D1

15″ subwoofer · dual 1 Ω · 2,500 W RMS

Fs 29.9 HzQts 0.49Vas 1.11 ft³Xmax 1.18″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 2,500 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 volume1.48 ft³ (42 L)
Qtc0.65
Fc40 Hz
F3 (−3 dB, no cabin gain)45 Hz
Example box (outside)16 15/16″ × 16 15/16″ × 13 5/16″
Open sealed box in designer

Ported

Net volume2.37 ft³ (67 L)
Tuning (Fb)26 Hz
Portround port Ø3″, 9 9/16″ long
Port velocity at 2,500 W531 ft/s
F3 (−3 dB, no cabin gain)23 Hz
Example box (outside)24 9/16″ × 17 11/16″ × 13 3/8″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs29.9 Hz
Qts0.49
Qes0.55
Qms4.87
Vas1.11 ft³
Re (one coil)0.8 Ω
Sd≈ 124 in²
Xmax1.18″
EBP54 — sealed or ported calc.
Sensitivity, 1 W / 1 m83.8 dB calc.

General

Size15″
Voice coilsdual 1 Ω
RMS power2,500 W

Mounting dimensions

Ø15 1/2″cutout Ø13 15/16″mounting depth 10 7/8″magnet Ø9 11/16″
Cutout diameter13 15/16″
Mounting depth10 7/8″
Overall diameter15 1/2″
Magnet diameter9 11/16″

The spec sheet's Sd of 177 in² is the area of a 15″ circle, not the cone's radiating area — not used.

Judging by its value, the published Re is for both coils in series — converted to per coil.

“≈” 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 15″ models