Page:Popular Science Monthly Volume 90.djvu/45

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Seeing the Sounds That You Sing

Clear pictures are made of the vibrations of your voice so that 5'ou can detect by sight an error - in pitch

��IS it difficult for you to sing in tune? Do you distrust your ear? Cheer up! there is hope. You can!'find' yourself by your eye. You can stand be- fore an instru- ment and see in clear pic- tures every pitch move- ment of your voice as 30 u are singing; you can see ex- a c 1 1 >' how many vibra- tions per sec-

���The tonoscope in the psychological laboratory of the Univers- ity of Iowa. It registers the pitch of the tone played or sung

��five dots so placed that, when acted upon by a sen- sitive light, they arrange themselves in characteristic figure forevery possible pitch within the range of the human voice. Each figure points to a number which indicates the pitch. The dots are ar- ranged into one hundred and ten rows; the first one

��ond your vocal organs are producing, and you can thus tell, at the very moment of singing a note, what error is involved.

Moreover, the player of the violin, flute, cornet, or other instrument, may treat his instrument in the same way. A person many hundreds of miles away may connect "long distance" with this "musical eye" and project the vibrations of his instrument on the screen. There is, indeed, no limit to which the musician may not go in improving his playing.

The instrument which will do all this is the tonoscope. As yet, there is only one tonoscope available, and that is in the

��has one hundred and ten dots, the next one, one hundred and eleven dots, and so on, each successive row having one more dot than the preceding one, up to the last, which has two hundred and nineteen. When a musician is singing before the instrument and sounds a tone, the row which has the dot frequency that cor- responds to the vibration frequency of the tone will stand still, while all other dots move and tend to blur. The row which stands still, therefore, points to a number on the scale which designates the pitch of the tone. In other words, to see the pitch of the tone, one has only to see the number

��psychological laboratory' of the University of the line that stands still.

��of Iowa. Professor Carl E. Seashore says: "It furnishes us the first ready and at the same time reliable and accurate means of registering directly the pitch of a tone as sung, spoken, or played with a musical instrument in such form that it can be operated with convenience and safety out- side the technical laboratory."

In brief, the instrument works on the principle of motion-pictures. It converts the sound vibrations into pictures on a screen. The screen, which may be seen through the opening in the front of the in- strument, has eighty thousand and ninety-

��The tonoscope is operated by electric current, which enables it to run indefinitely without disturbance. The speed of the revolving screen is controlled by a tuning- fork with which it must keep step, being driven by a synchronous motor. The instrument indicates the actual pitch of. any note to an accuracy of often less than a hundredth of a tone. Even if a note as constant as that of a tuning-fork is sounded, the pitch is recorded accurately in tenths of a vibration, because fractions of vibra- tions may be read in terms of the number of dots that pass per second.


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