Methods and apparatus for controlling the output of moving armature transducers

摘要: A moving-armature transducer assembly suitable for use as an alerter in a portable telephone. The includes housed enclosure including first and second acoustical chambers. sound emitted from front hole on side of the is propagated through chamber port assembly. rear phase-shifted by acting combination with or ports to have phase coinciding sound. then combines sound, reinforcing producing combined having increased level bandwidth.