B 21

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Extra Low End | Vigorous | Fundamental

B-21 is a multi-purpose passive bass-reflex subwoofer with high power SE Audiotechnik 21″ woofer.

Extremely flat frequency response extends down to 25 Hz.

Smart design ensures easy handling and operation in various applications, including cardioid subwoofer stacks.


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Port design

Aerodynamic port design reduces distortion and airflow noise. The unique asymmetric shape reduces port noise drastically by (-35 dB).

Sockets at front grill

Convenient multiple Neutrik speakON® sockets in front and back allows for easy set up ideal for live performances.
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Octopus feet

The so called “octopus feet” are made from some flexible rubber/plastic material, which provides good slip resistance.

Cardioid subwoofer setups

Due to the intelligent stacking design and the front and rear sockets, it is possible to operate our B-Line subwoofers as a cardioid setup without any problems.
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Model:B 21 / B 21W
Type Bass-Reflex, Subwoofer, passive
Transducers: 1x 21" with 5" Voice Coil
Impedance (Ω): 8 Ω
Coverage (°): omni directional
Low frequency SPL Limit (-3dB): 31 Hz
Sensitivity SPL (1m / 1W): 100 dB
Max SPL (@1m) *: 142 dB
Power rating (RMS** / Program** / Peak***): 1000 W / 2000 W / 4000 W
Amplifier: none (passive)
Connector(s): 2x Speakon®
Rigging: n/a
Cabinet: 15 mm plywood, black or white polyurea coating
Dimensions (WxHxD): 585 x 672 x 829 mm
Weight (kg): 49 kg

* max. SPL peak = Sensitivity + 10 x (log10 RMS Power) + 12 dB crest factor
** All product specifications are subject to change without prior notice.


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B 21 Dollyboard

Dollyboard for B 21

B 21 Dollyboard

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M-F3A SPS 20

M20 Pole support to mount M-F3A PRO (or M-F3A) on top of our subwoofers

M-F3A SPS 20


Specification Sheet