Fire resistant sound reproduction system - includes active and passive loudspeaker in sealed enclosure to provide better HF and extended LF reproduction

摘要

The fire resistant sound reproducing system comprises an active loudspeaker (10) and a passive loudspeaker (20) mounted on the opposing perforated faces (101, 102) of respective halves of an enclosure (100). The active loudspeaker (10) is controlled through a matching transformer (30) and a function switch (40). The two halves of the enclosure (100) are hinged together to provide a sealed interior with the loudspeakers being sealed to the perforated faces (101, 102). Each loudspeaker membrane is sealed with varnish. The active loudspeaker (10) provides improved high frequency reproduction while the passive loudspeaker (20) extends the low frequency range. The enclosure is filled with absorbent material such as fibre glass (50) to reduce resonance and improve coupling between the loudspeakers. The system is useful for public buildings, in mines, noise-filled workshops and for military uses.