Blaupunkt GBw 120

12″ subwoofer · 4 Ω · 400 W RMS

Fs 32 HzQts 0.50Vas 1.36 ft³
The published specs don’t add up:

Recommended box

For a sedan, one sub, 400 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 volume0.88 ft³ (25 L)
Qtc0.80
Fc51 Hz
F3 (−3 dB, no cabin gain)48 Hz
Example box (outside)14 3/16″ × 14 3/16″ × 11 15/16″
Open sealed box in designer

Ported

Net volume2.83 ft³ (80 L)
Tuning (Fb)28 Hz
Portslot 1 3/4 × 14 5/16″, 26 1/2″ long
Port velocity at 400 W65 ft/s
F3 (−3 dB, no cabin gain)25 Hz
Example box (outside)31 1/2″ × 15 3/4″ × 15 1/4″
Open ported box in designer
203040506080100150200606672788490HzdB
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain

Thiele/Small parameters

Fs32 Hz
Qts0.50
Qes0.597
Qms3.18
Vas1.36 ft³
Re3.2 Ω
Sd≈ 76 in²
Xmax≈ 0.39″
EBP54 — sealed or ported calc.
Sensitivity, 1 W / 1 m85.3 dB calc.

General

Size12″
Voice coils4 Ω
RMS power400 W

Mounting dimensions

Ø12 1/2″cutout Ø11 1/16″mounting depth 5 5/8″magnet Ø≈ 7 3/16″
Cutout diameter11 1/16″
Mounting depth5 5/8″
Overall diameter12 1/2″

“≈” 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 Blaupunkt 12″ models