AID TO PUBLIC SPEAKERS

Evening Star, Issue 21784, 28 July 1934, Page 4

AID TO PUBLIC SPEAKERS

An inconspicuous little roiei'ophouc no larger than a matchbox, weighing only three ounces, amt designed to. be fastened to tho coat lapel of a public speaker or entertainer, was the subject of a joint technical paper delivered by Dr Hairy l'\ Olson ami Richard \V. {liivlislu, research engineers of the U.C.A. Victor Company, before the Institute of Radio Engineers, in Philadelphia. The remarkable little device wag worn by the Camden engineer Who delivered the paper as a praeticS)! demonstration of tho uppliciitioh of the new microphone, aud carried the voice (if the speaker through aii amplifying system to all parts of tho large meeting room with extraordinary clarity. The outstanding features of the new lapel microphone are that it does hot pick up mechanical vibration froth the speaker’s chest or from body inoverneuis, and it permits the speaker to prove round freely without causing any appreciable change in the intensity or quality of. his voice. Another advaiw tage is that tho audieiice’s view of the speaker is Unobstructed by. bulkier apparatus. The new microphone, is expected to find a useful application pot only for public speaking and broadcasting, but also for sound newsreel work.

The new lapel microphone employs the velocity principle of operation." A thin aluminium ribbon is suspended in a magnetic field, and is operated by the varying pressure on the ribbon resulting' from the sound waves of tlie human voice. Advantage is taken in tho design of the fact that. this type of microphone is equally sensitive front and back, and when in use it is so arranged that the optimum sensitivity lies in the direction of the mouth when tlie speaker’s head is turned to either side .away from tlie microphone. . A .high "degree 'of ’ fidelity in reproducing the voice is assured by the ability of the. mechanism to reproduce tones from $0 to 7.000 cycles uniformly.