Cone Loud-speakers

Radio Record, Volume IV, Issue 47, 5 June 1931, Page 17

Cone Loud-speakers

X ‘Cause of Chattering GG0op as they are, balanced-armature loudspeaker units occasionally develop a form of "zizzing" or chattering, the cause of which may be exceedingly hard to track down. One of the most Obscure faults which may cause this extremely unpleasant accompaniment of speech and music is a defective joint. In all units the armature takes the form of a strip of soft iron to which the connecting rod is fixed either directly or through a lever mechanism. Now lightness is essential in the armature: and its associated parts, hence makers usually solder the rod or the lever to the armature. Iron is difficult material to solder well, and what is known as a "dry" int may easily escape detection at he factory. The joint looks all right, and at first feels all right. When the component has been in use for some little time the vibration to which the armature is subjected causes the joint to give way, with the result that the lever of the connecting rod itself becomes loose in its seating. "Zizzing"’ then sets in, growing steadily worse as the looseness increases.