Review Questions

1. Name several important reasons why the fundamentals of acoustics should be understood by communication engineers.

2. Explain the differences between, the objective and subjective interpretations of sound.

3. Explain how a continuous complex sound can be analyzed.

4. Discuss the phenomena that occur when a sound wave strikes a rigid wall. Repeat for a non-rigid wall that can vibrate.

5. If two sounds of slightly different frequencies and moderate intensities are simultaneously produced in air, is a beat frequency note created in the air? Explain the phenomenon that does occur.

6. What is meant by reverberation? What is the definition of reverberation time? How can a simple and approximate measurement of reverberation time be made?

7. What contributions were made by W. C. Sabine? Define the unit, sabine.

8. Why does the method of mounting a material affect its sound-absorbing properties? Does painting affect the sound-absorbing properties of a material?

9. What is the practicable method of reducing reverberation time? Why may the reverberation time be longer for music than for speech?

10. Enumerate the important considerations in the design of broadcast studios. Is a dead-air space between studio walls effective as sound insulation?

11. How are the sounds of speech produced?

12. Discuss and compare the frequency characteristics of speech and of music,

13. Discuss and compare the power in speech and musical sounds.

14. What studies have been made of the band-width requirements for radio programs, and what conclusions have been drawn?

15. Define noise. Why is it objectionable?

16. Describe the human ear and the process of hearing.

17. What is the field of audition, and what is its importance in communication.?

18. Define loudness, and explain how it differs from sound intensity.

19. What is meant by a threshold shift?

20. Describe a sound-level meter.

21. In making noise measurements, how do you correct for background noise?

22. Discuss the theory of noise reduction.

23. Explain the difference between articulation and intelligibility tests.

24. What are the effects of removing the high-frequency components from speech, and from music?

25. What are the effects of removing the low-frequency components from speech, and from music?