d&b Audiotechnik B4 Subwoofer

These units may show signs of heavy wear but are in good working condition.

The d&b audiotechnik B4-SUB is an actively driven cardioid subwoofer designed for accurate low-frequency reinforcement in live sound and installed audio where controlling bass spill is critical. Powered by a single amplifier channel, it delivers focused energy to the audience while minimizing unwanted output behind the system, helping reduce low-frequency buildup on stage and in reflective rooms.

Integrated cardioid design for cleaner low end

The B4-SUB houses two long excursion neodymium drivers in an integrated cardioid setup: a 15" driver in a bass-reflex design facing to the front and a 12" driver in a two chamber bandpass design radiating to the rear. The cardioid dispersion pattern resulting from this approach avoids unwanted energy behind the system that greatly reduces the reverberant field at low frequencies and provides the greatest accuracy of low frequency reproduction.

System integration and deployment

Because it is actively driven and optimized for cardioid performance, the B4-SUB is intended for use with d&b amplifier platforms and system processing. It can run in standard mode with a frequency response (-5 dB standard) of 40 - 150 Hz, or in 100 Hz mode with a frequency response (-5 dB 100 Hz mode) of 40 - 100 Hz when a tighter low-frequency range is preferred.

Maximum sound pressure is 128 dB with 10D, 131 dB with D25/25D, and 131 dB with D40/D80/D90/40D. Nominal impedance is 6 Ω, power handling capacity (RMS/peak 10 ms) is 500/2000 W, and up to 2 cabinets can be driven per amplifier channel. Connections are provided via 2 x NLT4 F/M.

Physical details

Dimensions (h x w x d) are 476 x 580 x 700/800 mm (18.7 x 22.8 x 27.73/31.6"), and weight is 44 kg (97 lb).

The B4 subwoofer can only be used in a ground stacked setup.