AID FOR THE DEAF

Wanganui Chronicle, Volume 74, Issue 144, 20 June 1931, Page 6 (Supplement)

AID FOR THE DEAF

MERIT OF SOUND PICTURES. QUESTION OF VIBRATIONS. “Talking pictures are doing a great deal of good for the hearing of the world,” states Douglas Shearer, a bro ther of Norma Shearer, and a promln ent member of the Metro Golawyn Mayer technical staff. “In the case where an car is inefficient due to some physical cause, constant use is valuable exercise, and talking pictures, in which the sound vibrations are impelled by *i mechanical force, and directed by a horn, arc much more easily heard than human speech. People who arc hard ot hearing will say that they can hear talking pictures, in which the sound vibrations are impelled by a mechani cal force, and directed by a horn, am much more easily heard than human speech. People who are hard of hearing will say that they can hear talking pictures far better than natural voices. This is on the same principle as the accousticon, or little telephone receiver, and microphone worn by many so afflicted. “All ears are not alike. A dog’s ears are for instance, attuned to a higher frequency' than human ears; in other w’ords, a dog will hear a note of much higher frequency than we can. Incidentally, the higher the frequency of tho note or the faster the vibrations, tho higher the note is. The bass tones of an organ for instance,are caused by vibrations that measure around a hundred to the second in the lowest pipes. Sometimes you feel rather than hear

them. The shrill noto of a piccolo means a vibration of about 20U0 impulses in the same second. “The voice produces these vibrations by’ means of the vocal -cords, which loosen and tighten to produce different notes —just as loosening and tightening the string of a violin changes its pitch by changing the rate of its vibration. A short string will pioduce a higher note than a long one. This is on the same principle as the pendulum. Affix a weight to a string two feet long and let it swing. It will swing slowly. Now shorten the string to six inches. Note how much faster the rate of speed. A long tuning fork blade does the same thing. It travois more slowly than the short blade, which vibrates rapidly. So sound waves come in short and long impulses according to their frequencies. ‘‘The medical fraternity of to-day uses a horn and amplifier such as we use in pictures to provide “limbering up” exercises for defective ears. In the treatment, a certain frequency is played over a stated period, to agitate the ear drum at a certain speed. Inaudible notes, or slow vibrations, arc sometimes prescribed. “Certainly those frequencies are contained in the wide range of the talking pictures, and possibly, tho physician could find many other frequencies equally as effective in the same picture. “Engineers in the past years have done much to make the sound in talking pictures better —by which I mean more pleasing to the hearer, and more accurate in relation to the sounds in real life. We have made sounds that can be more readily enjoyed, recognised, or in other words “more easily heard.” And every day sees new improvements. ’ ’

Norman Foster, Paramount featured player, has completed a six' reel picture of his recent trip around the world.