URAL Bulava 12 (2+2)

12″ subwoofer · dual 2 Ω · 900 W RMS

Fs 26.9 HzQts 0.43Vas 1.59 ft³Xmax 1.10″

Recommended box

For a sedan, one sub, 900 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 volume0.71 ft³ (20 L)
Qtc0.78
Fc48 Hz
F3 (−3 dB, no cabin gain)47 Hz
Example box (outside)14 9/16″ × 14 9/16″ × 9 9/16″
Open sealed box in designer

Ported

Net volume2.19 ft³ (62 L)
Tuning (Fb)27 Hz
Portslot 2 3/8 × 14 5/16″, 51 7/8″ long
Port velocity at 900 W62 ft/s
F3 (−3 dB, no cabin gain)25 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 15 11/16″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs26.9 Hz
Qts0.43
Qes0.48
Qms4.63
Vas1.59 ft³
Re (one coil)≈ 1.7 Ω
Sd75.7 in²
Xmax1.10″
Vd83.5 in³ calc.
Mms263 g calc.
BL12.5 T·m calc.
EBP56 — sealed or ported calc.
Sensitivity, 1 W / 1 m84.6 dB calc.

General

Size12″
Voice coilsdual 2 Ω
RMS power900 W

Mounting dimensions

Ø12 13/16″cutout Ø11 1/4″mounting depth 5 15/16″magnet Ø6 11/16″
Cutout diameter11 1/4″
Mounting depth5 15/16″
Overall diameter12 13/16″
Magnet diameter6 11/16″

Cone area (Sd) calculated from Fs, Vas and Mms: 75.7 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 URAL 12″ models