The Bosch LBD3905-D is a 12W bi-directional cabinet loudspeaker specially designed for clear announcements and background music in professional public address (PA) systems. With its bi-directional sound output, this speaker delivers audio evenly in two directions, making it ideal for corridors, hallways, passages, platforms, retail spaces, offices, schools, hospitals, and commercial buildings across India. Supporting 100V line PA systems and offering selectable power taps (12W / 6W / 3W), allows flexible sound control based on installation needs. Its wide sound dispersion, high sound pressure level, and clear frequency response (150 Hz – 15 kHz) ensure that announcements are loud, clear, and easy to understand even in long or narrow spaces. What is bi-directional sound in this speaker? A-1 Bi-directional means the speaker projects sound in two opposite directions, ideal for corridors and long spaces. What is the maximum power output of Bosch LBD3905-D? A-2 The speaker supports 12W maximum, with selectable taps of 12W / 6W / 3W. Is this speaker suitable for PA systems? A-3 Yes, it is designed specifically for 100V line public address systems. Can it be used for music as well as announcements? A-4 Yes, it supports clear speech and background music. Is installation easy? A-5 Yes, it includes rear wall-mount keyholes and push-in terminals for easy installation. Specifications Brand Bosch Model LBD3905-D Product Type Bi-Directional Cabinet Loudspeaker Rated Power 12 W (Selectable taps: 12 W / 6 W / 3 W) Rated Input Voltage 100 V line Rated Impedance ~833 Ω Sound Pressure Level (SPL) ~96 dB @ 12 W / ~90 dB @ 1 W (1 kHz, 1 m) Effective Frequency Range 150 Hz – 15 kHz Horizontal Coverage (-6 dB) ~254° @ 1 kHz / ~254° @ 4 kHz Vertical Coverage (-6 dB) ~254° @ 1 kHz / ~254° @ 4 kHz Connector Type 4-pole push-in terminals Mounting Wall mount (keyholes at rear) Dimensions (H × W × D) 243 × 230 × 131 mm Weight ~1.9 kg Colour Black Operating Temperature -5 °C to 55 °C Storage Temperature -40 °C to 70 °C Ideal Applications Offices, schools, hospitals, retail spaces, corridors, PA systems
