B 21

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.


B 21

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.
B 21
B 21

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.
B 21


Model:B 21 / B 21W
Type Bass-Reflex, Subwoofer, passive
Transducers: 1x 21" SE Audiotechnik woofer (5" Voice Coil), neodymium magnet, paper cone
Impedance (Ω): 8 Ω
Coverage *: Omnidirectional
Low frequency SPL Limit (-3dB): 31 Hz
Sensitivity SPL *: 100 dB
Max SPL (@1m) **: 142 dB peak
Power rating (RMS / Program / Peak ***): 1000 W / 2000 W / 6000 W
Connector(s): 2x SpeakON® NL4 IN/LINK in the front grille, 2x SpeakON® NL4 IN/LINK in the back
Cabinet: 15 mm plywood, black or white polyurea coating
Dimensions (WxHxD): 585 x 672 x 829 mm
Weight (kg): 49 kg

* Half-space (1W / 1m)
** max. SPL peak = Sensitivity + 10 x log10 (RMS Power) + 12 dB crest factor
*** Peak Power = Average Power + 6 dB crest factor

- All product specifications are subject to change without prior notice. -


B 21

B 21 Dollyboard

Dollyboard for B 21

B 21 Dollyboard

B 21

M-F3A SPS 20

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

M-F3A SPS 20


Engineering Data Sheet


EU declaration of conformity - Passive Loudspeakers

  • Description
    B 21 EU declaration of conformity
  • Download