BC543 - Very high-output cardioid subwoofer

  • Double-tuned, bass-reflex loaded cardioid-control subwoofer system
  • Triple 18” woofer with all-carbon cone for high pressure loading
  • 5.3" voice-coils for low power compression and accurate performance
  • Large, centrally-located vent for improved breathing and low compression
  • Selectable cardioid rearward rejection patterns with up to 42dB rearward rejection
  • SIS pre-wired for very high damping and further reduced distortion (with ALC)

Product description

The BC543 is a self-contained, high-output cardioid subwoofer system for both permanent and portable applications. It is designed to offer a very high output, tight and accurate sub-bass response, as low-frequency extension of any Alcons pro-ribbon system.

By means of a front and rear located woofer configuration, in combination with dedicated processing, the system offers selectable cardioid low-frequency pattern control and excellent rear rejection (up to 42dB), without the need for additional cabinets.

Two state-of-the-art 18” long-excursion woofers with 5.3-in. voice-coil with vented triple-spider frame, Neodymium motor structure and all-carbon-fibre cone and dust cap are mounted in a direct-radiating configuration, with centrally-located X-Venting™; Taking more than 25% of the baffle surface, this port is designed to maximise the system’s breathing capacity, while minimising port-compression. The excursion capabilities of the 18” design, extends the output by 3.5dB compared to traditional 18” designs (not included in SPLpeak spec).

On the rear side, a single state-of-the-art 18” long-excursion woofer with 5.3-in. voice-coil, Neodymium motor structure and all-carbon-fibre cone and dust cap is mounted in a direct-radiating configuration, with Flank-Venting™ port; This folded port design enables optimal reflex-breathing, under minimal baffle dimensions.

The BC543 in road version is fitted with 12 handles for easy logistics.

The BC543 is powered and controlled by the ALC amplified loudspeaker controller; The ALC offers system-specific drive processing with dedicated optimisation, power and excursion protection, and hybrid filtering.

The preset library contains BC543 settings for sub/bass/punch response curves, as well as different cardioid patterns for maximum rear-/side-ward attenuation.

Through the SIS™ (Signal Integrity Sensing) circuit, the cable-length and connector resistance between the BC543 and ALC is completely compensated (system damping factor >10.000), for further increased accuracy and controlled cone-travel, resulting in a tighter sub and bass response.

Dimensional drawing

Technical specifications

Frequency response  
+/- 3 dB   35 Hz - 150 Hz
+/- 10 dB   29 Hz -
Sensitivity nominal   100 dB (40 - 100 Hz)
Nominal impedance   4 ohms/front, 8 ohms/rear
Recommended drive   Sentinel10, 1 pce. per 2 ch.
    (4 ohms/front, 8 ohms/rear)
Nominal SPL peak   135dB (Sentinel10 40 - 100 Hz)
    140dB (comparative)
Dispersion H x V   omni (rear not connected) /
    (hyper)cardioid

Physical specifications

System subwoofer, bass reflex
  front + rear
Drivers   2x AW18.6NDC/8 18”,
    X-Vented™ (front)
    1x AW18.6NDC/8 18”,
    Flank-Vented™ (rear)
Connectors   2x Speakon NL8 input/link
Physical dimensions   mm         inches
Height   1196        47.1
Width   596          23.5
Depth   976          38.0
Weight (approx.) BC543   135 kg      (298 lb)
Weight (approx.)
BC543i
  123 kg      (271 lb)
Warranty   6 years limited

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