Sundown Audio SLD-12 D2

12″ subwoofer · dual 2 Ω · 600 W RMS

Fs 43 HzQts 0.53Vas 0.95 ft³Xmax 0.47″
The published specs don’t add up:

Recommended box

For a sedan, one sub, 600 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 volume0.74 ft³ (21 L)
Qtc0.80
Fc65 Hz
F3 (−3 dB, no cabin gain)61 Hz
Example box (outside)14 3/16″ × 14 3/16″ × 10 7/16″
Open sealed box in designer

Ported

Net volume2.26 ft³ (64 L)
Tuning (Fb)35 Hz
Portslot 2 3/16 × 14 5/16″, 25 3/8″ long
Port velocity at 600 W62 ft/s
F3 (−3 dB, no cabin gain)31 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 13 3/16″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs43 Hz
Qts0.53
Qes0.691
Qms2.23
Vas0.95 ft³
Re (one coil)1.83 Ω
Sd82.4 in²
Xmax0.47″
Vd38.9 in³ calc.
Mms204 g calc.
BL12.1 T·m calc.
EBP62 — sealed or ported calc.
Sensitivity, 1 W / 1 m86.9 dB calc.

General

Size12″
Voice coilsdual 2 Ω
RMS power600 W

Mounting dimensions

Ø12 5/8″cutout Ø11 1/8″mounting depth 5 7/16″magnet Ø7 3/8″
Cutout diameter11 1/8″
Mounting depth5 7/16″
Overall diameter12 5/8″
Magnet diameter7 3/8″

The spec sheet's Sd of 114 in² is the area of a 12″ circle, not the cone's radiating area — not used.

Cone area (Sd) calculated from Fs, Vas and Mms: 82.4 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 12″ models