Swat SBT-12

12″ subwoofer · dual 2 Ω · 650 W RMS

Fs 30 HzQts 0.43Vas 1.80 ft³Xmax 0.71″

Recommended box

For a sedan, one sub, 650 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
Fc56 Hz
F3 (−3 dB, no cabin gain)53 Hz
Example box (outside)14 3/16″ × 14 3/16″ × 10 7/16″
Open sealed box in designer

Ported

Net volume2.40 ft³ (68 L)
Tuning (Fb)30 Hz
Portslot 2 3/16 × 14 5/16″, 33 3/4″ long
Port velocity at 650 W65 ft/s
F3 (−3 dB, no cabin gain)28 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 14 9/16″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs30 Hz
Qts0.43
Qes0.463
Qms6
Vas1.80 ft³
Re (one coil)1.9 Ω
Sd74.4 in²
Xmax0.71″
Vd52.7 in³ calc.
Mms180 g calc.
BL11.8 T·m calc.
EBP65 — sealed or ported calc.
Sensitivity, 1 W / 1 m86.7 dB calc.

General

Size12″
Voice coilsdual 2 Ω
RMS power650 W

Mounting dimensions

Ø≈ 12 3/8″cutout Ø11 3/16″mounting depth 6 9/16″magnet Ø≈ 7 1/4″
Cutout diameter11 3/16″
Mounting depth6 9/16″

Only Qts is published — Qms assumed to be 6 and Qes calculated (barely affects box design).

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 Swat 12″ models