We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
SPEECH, MUSIC, AND HEARING 247
Let us now consider for a few moments the physical nature of musical sounds. They are characterized by being sustained at definite pitches for a comparatively long time and by having the changes in pitch take place in definite steps called the musical interval — thirds, fifths, octaves, etc. There are two outstanding physical mechanisms besides the voice for producing musical tones; namely, vibrating strings and vibrating air columns. The piano and the violin are examples of the first; and the pipe organ, the flute, and horns are examples of the second.
A single note sounded by one of these musical instruments contains more than one frequency. The lowest frequency, called the fundamental, usually determines the pitch; but there is, in addition, a large number of component frequencies called harmonics, each being a simple multiple of the fundamental frequency. It is this abundance of harmonics that produces the richness of musical tones. The component having the lowest frequency usually but not always determines the pitch. It is very easy to produce, in the laboratory, musical tones having a definite pitch corresponding to 100 cycles without using any frequencies below 500 cycles. If pure frequencies of 500, 600, 700, and 800 cycles are sent into a receiver a musical tone of low pitch corresponding to 100 cycles is produced. The intensity of the sound during the rendition of an orchestral selection varies over very wide ranges, sometimes as much as 100,000 to 1. Naturally, this fact makes it difficult to handle the proper transmission of such music.
Musical instruments, to repeat, are divided into two classes — string instruments and wind instruments. Tones of string instruments, produced by plucking, striking, or bowing, usually are reinforced by resonating air cavities or sounding boards. Wind instrument tones are produced by the aid of reeds, as with the clarinet or flute, or by the