B 21

The B 21 comprises a single 21″ driver mounted in a vented box, with a sophisticated adaptive port that optimises the airflow and improves its response. This technology, developed through exhaustive research, enables a lower cut-off frequency while having smaller volume. This translates into deeper and dynamic bass from a compact enclosure.

In addition to the speakON® connectors on the back, the subwoofer includes two additional located on the front. This guarantees wiring flexibility and ease of use, reducing setup time even in large configurations.

Finally, the set of accessories specially designed for the B-Line, makes their setup and transportation easier, safer and more comfortable.

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Sockets at front grill

Sockets at front grill

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

Cardioid subwoofer setups

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 15A and B 15A W do not have any front sockets.

Starfish rubber-feet

Starfish rubber-feet

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


B 15

B 15A

B 18


B 21 4
B 21
Frequency range (-3 dB) *: 33 Hz - 130 Hz
Frequency range (-10 dB)*: 26 Hz - 160 Hz
Coverage angles (-6dB) [H x V]: Omnidirectional
Nominal impedance 8 Ω
Sensitivity**: 99 dB
Peak power: 4000 W
Continuous power ***: 1000 W
Maximum Peak SPL ****: 142 dB
System type: 1-way passive system
Crossover frequency: -
Transducers: 1 x 21" driver
Enclosure: Vented box
Connectors: Input / Link signal: 4 x Neutrik speakON® NL4
Link output: 1 x Neutrik SpeakON® NL4
Wiring: Pins 1+/1- : driver
Pins 2+/2- : link (Output CH 2, pins 1+/1-)
Product Dimensions [H x W x D] (Including Rigging): 666 x 585 x 832 mm
Net weight: 51 kg
Packaging dimensions [H x W x D]: 796 x 685 x 930 mm
Total weight: 61.5 kg
Cabinet: 15 - 24 mm plywood
Cabinet finishing: Black or white polyurea coating
Grille: Powder coated perforated steel
Hardware: 4 SE Audiotechnik® ergonomic handles
8 rubber feet and top recesses
M20 pole thread
Stacking: -
Splay angles: -
Pole bar: SPS20
Flight case: B21 FC
Transport dolly: B21 TD
Transport cover: B21 TC
All product specifications are subject to change without prior notice. * Measured with a 6th-order Butterworth low-pass filter applied at 130 Hz
** Half space, 1W / 1m, on axis
*** According to EIA-426B Standard (based on RMS Voltage)
**** Max Peak SPL = Sensitivity + 10log10(Continuous Power) + 12 dB Crest Factor



M20 Pole Support to pole mount an M-F3A or M-F3A PRO on any B-Line subwoofer

B21 FC

B21 FC
Flight case for B 21 subwoofer

B 21TD

B21 TD
Dolly board for B 21 subwoofer

B21 TC

B21 TC
Transport cover for B 21 subwoofer