Chapter 21

1. Chapter 21 Musical Sounds

2. The source of all musical sound is something • vibrating. • resonating. • under both tension and compression. • represented by a series of harmonics.

3. The source of all musical sound is something • vibrating. • resonating. • under both tension and compression. • represented by a series of harmonics.

4. What divides noise from music is most often • imaginary. • objective. • subjective. • nonexistent.

5. What divides noise from music is most often • imaginary. • objective. • subjective. • nonexistent. Explanation: Although the two can be discerned electronically, most often subjectivity is dominant.

6. As humans age, the range of sounds heard • expands. • decreases. • Both of these. • None of these.

7. As humans age, the range of sounds heard • expands. • decreases. • Both of these. • None of these. Comment: Looking for a career that will likely grow? Consider becoming an audiologist!

8. Low-pitched sounds have • low frequencies. • long periods. • Both of these. • None of these.

9. Low-pitched sounds have • low frequencies. • long periods. • Both of these. • None of these. Explanation: A low frequency has a long period. If you missed this, be careful in answering too quickly.

10. The notes of a piano keyboard differ in • pitch. • frequencies of sound they can produce. • wavelengths of sound they can produce. • All of these.

11. The notes of a piano keyboard differ in • pitch. • frequencies of sound they can produce. • wavelengths of sound they can produce. • All of these.

12. The frequency of a note one octave higher in pitch than a 440-hertz note is • 1760 Hz. • 880 Hz. • 440 Hz. • 220 Hz.

13. The frequency of a note one octave higher in pitch than a 440-hertz note is • 1760 Hz. • 880 Hz. • 440 Hz. • 220 Hz.

14. The fundamental frequency of a violin string is 440 hertz. The frequency of its second harmonic is • 220 Hz. • 440 Hz. • 880 Hz. • None of these.

15. The fundamental frequency of a violin string is 440 hertz. The frequency of its second harmonic is • 220 Hz. • 440 Hz. • 880 Hz. • None of these.

16. Joseph Fourier discovered that periodic waves can be represented by • a series of nonperiodic waves. • a binary code. • the sum of a series of simple sine waves. • heat propagation.

17. Joseph Fourier discovered that periodic waves can be represented by • a series of nonperiodic waves. • a binary code. • the sum of a series of simple sine waves. • heat propagation.

18. Our ears sort out the complex jumble of sounds that reach them. In so doing, our ears perform a sort of • Fourier analysis. • digital recombination of signals. • analog amplification. • pitch analysis.

19. Our ears sort out the complex jumble of sounds that reach them. In so doing, our ears perform a sort of • Fourier analysis. • digital recombination of signals. • analog amplification. • pitch analysis.

20. The loudness of a sound is most related to its • frequency. • wavelength. • intensity. • period.

21. The loudness of a sound is most related to its • frequency. • wavelength. • intensity. • period.

22. What is the threshold of human hearing? • 1 decibel • 10 decibels • 100 decibels • None of these.

23. What is the threshold of human hearing? • 1 decibel • 10 decibels • 100 decibels • None of these. Explanation: The threshold of hearing is 0 decibels (see Table 21.1).

24. Compared with a sound of 30 decibels, a sound of 60 decibels is • twice as intense. • 10 times as intense. • 100 times as intense. • 1000 times as intense.

25. Compared with a sound of 30 decibels, a sound of 60 decibels is • twice as intense. • 10 times as intense. • 100 times as intense. • 1000 times as intense. Explanation: Scaling sound intensity by factors of 10, we find that 30 dB is 103 times as intense as the threshold of hearing, and 60 dB is 106 times as intense as the threshold of hearing. Note that 106 (1,000,000) is 1000 times greater than (103) 1000. So sound at 60 dB is a thousand times as intense as sound at 30 dB.