B-Line 21″

The Powerhouse

B 21
B 21 (Rückansicht)
B 21 W
B 21 W (Rückansicht)
B 21A
B 21A (Rückansicht)
B 21A W
B 21A W (Rückansicht)

The mighty 21″ driver with its huge 5″ voice coil thunders with up to 142 dB max. SPL down to the deepest depths – performing from 25 Hz it is the bass beast in our line-up.

With a load capacity of up to 4,000 W peak, it delivers enough power for every stage and every event. Despite its higher weight, it is easy to manoeuvre thanks to the two wellpositioned recessed grips on both sides.

In direct comparison, as expected, it delivers the most robust performance at the low end and generates more than enough pressure in any situation.

The active versions of this bass monster have a 1,600 W Class-D amp on board.


The great advantage of powered speakers is the built in amplifier. So there is no need for an external device – the internal amp is optimally matched to the woofer! The B 21A is driven by a mighty 1,600 W
(peak) Class-D amplifier. Integrated DSP presets allow loading of preset system setups that are optimally matched to SE Audiotechnik products.

Thus, the entire system is quickly and easily set up and perfectly adjusted. The directivity can be effortlessly changed in a flash from normal to cardioid or end-fire configuration via the large display and the push/rotary controller.

Parameters such as EQ, Delay, Sensitivity and Phase can be adjusted and stored in your own User Presets.

B 15A FS, Rückansicht
Airflow B21

Products of the 21'' - Series

B 21
B 21A


B15 Drawing

Model:B 21B21A
Frequency range (-3dB) *:33 Hz – 130 Hz33 Hz – 230 Hz
Frequency range (-6dB) *:26 Hz – 160 Hz27 Hz – 280 Hz
Coverage angles (-6dB) [H x V]:OmnidirectionalOmnidirectional
Nominal impedance:8 Ω8 Ω
Sensitivity **:99 dB
Peak power:4000 W1600 W
Continuous power ***:1000 W
Maximum Peak SPL ****:142 dB139 dB
System type:1-way passive system1-way self-powered system
Transducers:1 x 21″ driver1 x 21″ driver
Enclosure type:Vented boxVented box
Connectors:Input / Link signal: 4 Neutrik speakON® NL4
Link output: 1 Neutrik speakON® NL4
Input signal: balanced XLR 3-pin female
Link output: balanced XLR 3-pin male
Power input: powerCON® 20A
Power link output: powerCON® 20A
Wiring:Pins 1+/1- : driver
Pins 2+/2- : link (Output CH 2, pins 1+/1-)
Pin N: Neutral
Pin L: Conductor
Pin E: Ground
Product dimensions [H x W x D] (Including rigging):666 x 585 x 832 mm666 x 585 x 832 mm
Net weight:51 kg55 kg
Packaging dimensions [H x W x D]:796 x 685 x 930 mm796 x 685 x 930 mm
Total weight:61.5 kg65 kg
Cabinet:15 – 24 mm plywood15 – 24 mm plywood
Cabinet finishing:Black or white polyurea coatingBlack or white polyurea coating
Grille:Powder coated perforated steelPowder coated perforated steel
Hardware4 SE Audiotechnik® ergonomic handles
8 rubber feet and top recesses for stacking
M20 pole thread
4 SE Audiotechnik® ergonomic handles
8 rubber feet and top recesses for stacking
M20 pole thread
Stacking:Two-point SE Audiotechnik® stacking systemTwo-point SE Audiotechnik® stacking system
Pole bar:SPS20SPS20
Transport dolly:B21 TDB21 TD
Transport cover:B21 TCB21 TC
Amplifier rain cover:P801DL RC
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



SPS 20

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

B 21 Dollyboard

B21 TD

Dolly board for B 21 subwoofer