Electro acoustic transducer with air space behind membrane - has space subdivided by sound attenuating material to maintain LF efficiency

摘要

The electroacoustic transducer has a similar construction for both microphne and loudspeaker. The loudspeaker has the air space (10, 12, 13) behind the membrane (16) divided by sound attenuating material (9). This closed air spece is formed by a toroidal space (13) around the magnet (3), by axially parallel recesses (10) in an insert (8) coaxially around the magnet, and by a toroidal space (12) beneath the insert. The insert consists of a felt ring with the recesses on its inner surface. The advantage of this structure for the loudspeaker (and of a similar structure for the microphone) lies in being able to select the working frequency range without affecting LF efficiency.