472 ENERGY MAY BE PROPAGATED BY VIBRATIONS but capable of producing many more overtones. Such instruments would be so complex and so expensive, however, that few people could afford to purchase them. The Novachord uses vacuum tubes to produce electrical waves that are changed into sound just as radio waves are changed into sound in the radio loud-speaker. The Hammond Electric Organ uses synchronous motors to turn iron cogs near coils on magnets which thus generate alternating currents which are then converted into sound by the system used in a radio. In 1939 Hammond added a synthetic reverberation unit which gives the effects of a large organ in an auditorium. The Solovox is an inexpensive electrical musical instrument designed to supplement the piano by providing tone qualities which the piano cannot produce. The Human Voice Is the Most Versatile of Musical Instruments. The human voice is a reed type of instrument. The vocal cords act as the generator; and their tension, length, and thickness can be controlled by the muscles. The vibrations are produced by the flow of air controlled by changing the size and shape of the throat cavities and by closing and opening the lips. The amplifier consists of those cavities whose shape markedly affects the quality of the tones produced. STUDY QUESTIONS 1. What is music as differentiated from noise? 2. Why is it that some people can produce music from a given instrument while other people cannot do so? 3. How does the human voice produce sounds? 4. Why are some voices musical, while others are not? 5. What principles are used in different musical instruments — wind, string, drums, tympani — to produce sounds? 6. Ask some of your musical friends to explain the difference between grand and upright pianos and between cheap and expensive pianos. 7. Try to find out the difference between Occidental and Oriental music. 8. Upon what factors do pitch, intensity, and quality of sound depend? 9. What are two important parts of nearly all Musical instruments? 10. What does the elimination of overtones do to sound? 11. What does the musician mean by the terms, harmony and discord? 12. What does a violinist do to his violin in order to tune it? 13. How can a violinist produce so many tones with so few strings? 14. Explain how the Novachord imitates many musical instruments. Why does the Novachord fail to give perfect imitations of musical tones which are very rich in overtones? 15. What is the function of the Solovox?
THE SCIENTIFIC BASIS OF MUSIC 473 16. How do the Novachord and Hammond Organ produce and control the pitch of musical tones? 17. In what respect could an orchestra, a band, or a choir be considered to be a supermusical instrument? 18. If a major chord begins on a tone whose frequency is 512, what are the frequencies of the other tones? 19. Explain the necessity for the black keys on a piano. 20. Account for the change in pitch as water is poured into a deep jar. 21. Explain the production of different tones with "musical glasses." 22. What is there in music that is not scientific? 23. Discuss the fact that a person with "absolute pitch" may not be musical.