BQ211 - compact high-output subwoofer

  • Double-tuned, quarter-wave loaded high-impact subwoofer system
  • 21” woofer with all-carbon cone for high pressure loading
  • Large, rounded vent for improved breathing and low compression
  • Force-ventilated 5.3" voice-coil for low power compression prolonged performance
  • SIS pre-wired for very high damping and further reduced distortion (with ALC)
  • Front-positioned NL4 connector for easy cardioid connection

Product description

The BQ211 is a quarter-wave loaded subwoofer system, extending the low frequency response of Alcons’ pro-ribbon systems, in both permanent and portable applications. Featuring a state-of-the-art 21” Neodymium transducer, this subwoofer is designed to offer maximum, prolonged high impact SPL performance from a relative small footprint.

For this, the latest materials and innovations have been applied: A very large displacement transducer with all-carbon fiber cone + dust cap, 5.3” voice-coil with vented triple-spider frame plus optimized low resistance impedance, and port-vented magnet structure to maximally reduce power compression.

The extensively internally-braced cabinet features features double-tuned, high-pressure loading, through a rounded 236mm/9.3” diameter low-tuned bass-reflex vent and a wide, high-tuned quarter wave tunnel. This provides optimised breathing at high SPLs, yet keeping the total system weight to a minimum.

Slider feet on cabinet bottom and side enable stacking of multiple BQ211’s into vertical LF arrays: The additional front-positioned NL4 connector caters for easy “reverse connection” in cardioid arrays.

The BQ211 is driven and controlled by the ALC amplified loudspeaker controller, for maximum sound quality and output power with long-term operation reliability. The integrated factory presets in the drive processor of the ALC offer gain, phase and filtering matching with all Alcons top systems.

The BQ211 is SIS™ pre-wired: Through the Signal Integrity Sensing circuit of the ALC, the cable-length and connector resistance between the BQ211 and ALC is dynamically compensated (system damping factor 10.000), further reducing distortion, while increasing response accuracy.

The BQ211 is available in road-version and installation (“i”) version, without handles and wheel dolly board. Through the Architect Color Option™ program, the BQ211i can be finished in any RAL™ color.

Dimensional drawing

Technical specifications

Frequency response 34 Hz - 150 Hz (+/- 3 dB)
28 Hz - (+/- 10 dB)
Sensitivity nominal 100 dB (40 Hz - 100 Hz)
Nominal impedance   4 ohms
Recommended drive Sentinel10
Nominal SPL peak 134 dB (Sentinel10 40 Hz - 100 Hz)
139 dB (comparative)
Dispersion H x V omni / (hyper) cardioid
in array with processing



Physical specifications

System   subwoofer, bass-reflex +
quarter wave pipe
Drivers LF   1 x AW21.6NDC-4 21” double vented
Connectors   3 x Speakon NL4 input/link
Physical dimensions   mm        inches
Height   590         23.2
Width   746         29.4
Depth   986         38.8
Weight (approx.) BQ211   73 kg      161 lb
                             BQ211i   64 kg      141.1 lb
Warranty   6 years limited

Stay Tuned

Subscribe to the Alcons newsletter and stay tuned