URAL Bulava 15 (2+2)

15″ subwoofer · dual 2 Ω · 900 W RMS

Fs 25.7 HzQts 0.54Vas 3.73 ft³Xmax 1.18″

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 volume2.90 ft³ (82 L)
Qtc0.82
Fc39 Hz
F3 (−3 dB, no cabin gain)36 Hz
Example box (outside)31 1/2″ × 17 11/16″ × 12 1/4″
Open sealed box in designer

Ported

Net volume4.94 ft³ (140 L)
Tuning (Fb)27 Hz
Portslot 2 15/16 × 16 5/16″, 29 15/16″ long
Port velocity at 900 W61 ft/s
F3 (−3 dB, no cabin gain)24 Hz
Example box (outside)31 1/2″ × 17 11/16″ × 22 15/16″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs25.7 Hz
Qts0.54
Qes0.61
Qms4.73
Vas3.73 ft³
Re (one coil)≈ 1.7 Ω
Sd127.7 in²
Xmax1.18″
Vd150.8 in³ calc.
Mms349 g calc.
BL12.5 T·m calc.
EBP42 — suits sealed calc.
Sensitivity, 1 W / 1 m86.7 dB calc.

General

Size15″
Voice coilsdual 2 Ω
RMS power900 W

Mounting dimensions

Ø15 1/2″cutout Ø13 15/16″mounting depth 6 7/8″magnet Ø6 11/16″
Cutout diameter13 15/16″
Mounting depth6 7/8″
Overall diameter15 1/2″
Magnet diameter6 11/16″

Cone area (Sd) calculated from Fs, Vas and Mms: 127.7 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 15″ models