Making Sound Visible

Radio Record, Volume III, Issue 32, 21 February 1930, Page 3

Making Sound Visible

A Recent Invention Y means of a new device called the "projection osiso" it is now possible for vocal and instrumental artists to see as well as hear the sound waves produced while singing or playing, The ‘sound waves. are intercepted by a microphone and are conveyed electrically to an "osiso," which consists essentially of a delicately suspended mirror that oscillates in unison with the received sound waves. A beam of light directed on this mirror is reflected by it to a system of revolving mirrors which in turn reflect the beam,. and thus ‘project it upon a screen which may be viewed by any number of people. When all is quiet around the microphone, a long white line is seen upon the screen, but as. soon as any sound reaches the sensitive electrical ear the white line is agitated into waves. 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 sounds. Twe practical investigations are beinging carried out with the aid of this. instrument, the possibilities of which seem almost endless. Firstly, it is being used to study ‘the construction of pianos and other musical instruments in order to improve them. Jor example, if successive notes on a piano: are struck with the same force the ,osiso screen may indicate that some notes produce distinctly larger waves than others, This shows that these -particular notes, owing to some peculiarity. in ‘the construction of the instrument, produce louder sounds than the rest. . : _ Another application of this. instrument.is that of helping the musical student to improve his technique. .The sound waves produced by the touch of . a master pianist differ from those produced when the same keys-are struck by an unskilled hand. Permanent records of the. wave patterns. producéd by distinguished musicians: have been made by means of the older’ photo+ graphic type of osiso, 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. ‘

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