JARRING IN LOUD SPEAKERS

Manawatu Times, Volume LII, Issue 6454, 11 November 1927, Page 11

JARRING IN LOUD SPEAKERS

Frequently one hears jarring in loud speakers, the cause of which is not easy for the novice to determine. The following three points should ho given attention'when seeking to remedy the trouble,'; —

1. If the last amplifying valve is overloaded, the loudest notes will cause distortion, which may bo mistaken for blasting at the transmitting end. The moral here is to use a "power” valve and not to forgot the grid bias. 2. Be sure that the fixed condenser across the loud speaker is in good condition. This is a most difficult tiling to test with certainty unless expensive laboratory apparatus is available. It is best to try several replacements in this position. 3. In quite a number of eases the same effect may be caused by what is known as "resonance.” Glasses, wooden boxes, etc., will cause echo upon certain notes, and one has only to go close, to an open piano and sing a. few notes to hear the same repeated from the instrument perhaps softly, but nevertheless accurately.