“VELOCITY” MICROPHONE.

Waikato Times, Volume 114, Issue 19012, 1 August 1933, Page 7

“VELOCITY” MICROPHONE.

AN IMPROVED INSTRUMENT. MADE BY CHRISTCHURCH MAN. Although he chooses to remain anonymous, a Christchurch radio engineer who has been intimately connected with broadcasting in New Zealand since its Inception has constructed a microphone that Is the lirst of its type to be made in tho Dominion. From all points of view it is a definite improvement on tho “mikes” now In general use, and It has peculiar advantages that make it particularly suitable for talkie recording. This new “velocity” microphone is gaining favour in America, and It promises to bring about great changes in the quality and technique of radio broadcasting. It is actuated by the velocity of the minute air particles set In motion by sound waves, which are reproduced with a fidelity never before possible; ordinary diaphragm microphones have been cramped by their limited tonal tango, which could not reproduce all tones without some distortion—the rattling of a bunch of keys would sound like the Jangling of tin cans. There Is no diaphragm In the new microphone, but instead a sensitive ribbon of duralumin, the heart of the instrument, which vibrates with the variations of the air particles; if responds uniformly to the entire audible range of sound from zero to 1-4,000 cycles or over, which means that all the subtle louings-that

give light and shade—and therefore reality—to recording are faithfully mirrored. Diaphragms offer a relatively large and Impeding surface to sound waves, but In the new Instrument the metal ribbon —which is only one three-thousandth of an inch in thickness —Is suspended on a magnetic field, thus enabling the sound waves to pass through freely. Another important feature Is that the instrument Is bl-directlonal, sounds coming from two directions being produced. This is an Important step forward in studio and talkie work, for the director can stand on the “blind” side of the Instrument and give his No longer is it necessary to crowd performers on one side, as entertainers can say their lines facing each other, and orchestras in large ensemble effects can be placed more advantageously. The “mike” has a sighting screen similar to that on a camera, the sounds from ail speakers, singers or Instruments within the range being recorded. In movie studios the grind of the camera can be eliminated, and wherever the microphone is placed the recorded or broadcast sound is free from echo effects.