balanced armature unit

balanced armature unit

[′bal·ənst ′ärm·ə·chər ‚yü·nət]
(engineering acoustics)
Driving unit used in magnetic loudspeakers, consisting of an iron armature pivoted between the poles of a permanent magnet and surrounded by coils carrying the audio-frequency current; variations in audio-frequency current cause corresponding changes in armature magnetism and corresponding movements of the armature with respect to the poles of the permanent magnet.