SEEING SOUND WAVES.

Auckland Star, Volume LXI, Issue 217, 13 September 1930, Page 8 (Supplement)

SEEING SOUND WAVES.

DEVICE TO HELP MUSICIANS. SEE AS WELL AS HEAR, THEIR OWX MUSIC. INVENTION'S MANY USES. By means of a new device, known as ne the projection osiso, it is now possible for singere, speakers, actors, pianists, violinists, and other vocal and instrumental artists to see the sound waves they produce dance visibly across a ecreen, just as they dance invisibly through the air to the ears of their audience. This device was developed by the Westinghouse Electric and Manufacturing, Company. It consists of several different, parts. Tho sound waves are caught by a microphone, which can be placed in an convenient location, and are conveyed electrically to an osiso, which consists essentially of a delicately suspended mirror that is oscillated in unison with the received sound waves. A ibeain of light,. directed on this mirror, is reflected by it to a system of revolving mirrors, which, in turn, project it upon a screen where it can be viewed by any number of people.

When all is quiet around the microphone, a long -white line is seen on the screen, but as soon as any kind of a sound reaches the sensitive electrical ear, the white line on the screen is thrown into waves, much as a clothes line is thrown into waves when its end is shaken. The form of these -waves varies with the sounds producing them, and they range from gentle ripples, produced by low pure tones, to the most intricate of patterns produced by loud complex chords and noises. "Two practical investigations are now being carried on with the aid of the projection osiso," stated Mr. W. B. White, acouetic engineer of the company, "although its possibilities seem almost endless. As Individual as a Signature.

"In the firet place, we are using it to study the construction of -pianos and other musical instruments in order to improve them- You need only watch the waves formed on the screen to notice that when I strike successive keys on this piano, though I strike each with approximately the earae force, some notes produce distinctly larger wav.esl than others. This nieane that those particular notes produce louder sounds than the rest, due to eome peculiarity in the construction. Your eye can see it although, if you are not a musician, your ear may not detect the difference. Secondly, when I strike , various notes and then hold the loud pedal down after each, you can readily see that the vibrations 'last longer in some caeee than they do in others, which shows that the sounding board, reverberates 'better at some points in the scale than at others. Such characteristics, together: with others which only an. expert would notice, are investigated when once detected and in due course eliminated. "Another application of this instrument," continue-' Mi'. WOiite,, "is to help the student improve his technique. Ihe sound waves produced by the touch of a master pianist differ from those' pro-] duceel when the same keys are- struck by an unskilled hand. Permanent records of the wave patterns produced by distinguished musicians have been made by means of the older photographic type of osiso in the- acoustical laboratory, and, with these before him, the student can endeavour to reproduce them on the screen of the projection osiso. It seems certain ; that improvement can be attained in this way, but it certain that no amount of effort will transform a good clerk into a great artist, for. one of the things that the osiso has demonstrated is that each artist produces patterns as individual as his signature, and though others may ' be able to imitate these patterns fairly well as a good forger can imitate a Bignature, apparently no one else can reproduce them exactly. The artist s personality, therefore, remains the principal element in the secret of the power he exerts over his audience.

"Obviously, however, the grosser errors in playing, singing and speaking can be overcome with the help of this instrument, since, with the eye to aid the ear, an error can be more readily appreciated and its correction effected.

Help Deaf To Articulate. "Master musicians are also interested in studying the details of their own technique. For example, one well-known pianist has learned by osiso sound wave photographs that he can produce a single note with at least 18 different gradations, each individual both in tune, colour and loudness. He can thus determine the actual difference between his "cantabile" and his accompaniments! notes, between his "forte" and his "fortissimo," and so on. Though great artists are in many ways beyond instruction, they nevertheless gam mucJi from accurate information as their own work, and the osiso is capable of showing them many things that have heretofore escaped direct observation. To mention one small detail, _we were able to show one musician that his finger nails made little'clicks when he struck the keys in a certain way, and though he -probably never realised that fact, this certainly had an effect, however minute on his playing, whether favourable or unfavourable is something for him to determine."

The osiso in its older form, which is euitable for photographing waves and for scientific work, has been used extensively in a wide variety of ..electrical and acoustical investigations. It is, tor example, the instrument used by Byrd s radio experts on the Antarctic Continent in their study of the behaviour of radio waves, and it is also being employed by Dr. - Max Goldstein for instructing the totally deaf to speak correctly. The present development, by magnifying the wave forms to any desired extent, enlarges its range of usefulness, especially in the educational field.